November 29, 2006

Metformin vs Metformin ER

I'm seeing quite a few posts on BBSes from people who are having problems with metformin because of side effects that could be eliminated if they were taking the extended release form of this drug.

For some reason, many family doctors don't seem to be aware that there is a ER version of this drug that has such benefits. This is probably because metformin is a cheap generic and isn't promoted by herds of beautiful ex-cheerleaders turned drug company salespushers who "educate" doctors about far more expensive--and less effective--newer drugs.

Here are the facts: Metformin (also sold under the brand name Glucophage) comes in a regular version which is taken at meal time, three times a day, and an extended release form (marketed as ER or XR) which is taken once a day.

Almost always, when people report diarrhea or intense heartburn with metformin, they are taking regular version. I experienced the heartburn on the regular drug. It was very disturbing because the pain was localized over my heart and felt just like the description of a heart attack you read in articles. My doctor assured me it was coming from the metformin, but that didn't make it any easier to live with because I kept wondering how, if I were having a real heart attack, I'd know it wasn't a pain from the drug?

The ER version releases the drug more slowly and this usually eliminates the gastrointestinal problems.

The trade off with taking the ER form is that the amount of blood sugar lowering you see might be a bit less than with the regular form as the drug acts in a slower smoother fashion rather than hitting all at once. But if you can't take the regular at all drug because of the side effects, the slight weakening in effect is a reasonable trade off. Plus, you only have to remember to take one dose rather than three. For me, this is not a trivial benefit. Even remembering to take one dose a day is sometimes a challenge!

One important point that my doctor missed when prescribing the ER version of metformin is this: The maximum dose of Metformin ER is LOWER than the maximum dose of regular Metformin.

According to the prescribing information, the maximum dose of the ER is 2000 mg a day. That of the regular is 2550 mg/day. Don't count on a pharmacist to catch the error if your doctor prescribes too much. Mine didn't, but I felt distinctly unwell on the high dose, and a quick look at the prescribing information online showed me the error.

Fortunately, a metformin overdose appears to be surprisingly benign. People have survived suicide attempts where they swallowed as much as 85 grams of the stuff at once. (They did develop lactic acidosis, which can be fatal, but survived.)

The dose at which metformin is supposed to be effective for most people is 1500 mg per day, though I know some smaller people who find a dose of 1000 mg effective. Your body weight will make a difference here, so if you are very large, you may need the maximum dose. In any event, don't conclude that metformin doesn't work until you have tested the dose up to the maximum.

It also takes up to two weeks for the full effect of metformin to become evident. While I will see an increase in my blood sugars if I forget a single day's dose, if I stop the drug for two weeks I see a slow rise in blood sugars through this period. My guess is that this two stage effect is because metformin works both on the liver (where it reduces the release of glucose) and the muscle (where it tricks the tissue into thinking it has just exercised and thus ramps up its burning of glucose). Whatever the explanation, give the drug a few weeks to see what it really does.

Also, many people who experience gas after taking metformin find that cutting way back on their intake of starchy carbohydrates helps eliminate the problem.

Because you only take metformin ER once a day you might wonder what happens if you take it a few hours earlier than usual. Will this cause a dangerous overlap? My experience has been that this isn't a problem. I suspect that the drug does not release evenly over the 24 hours it is supposed to act, and by 20 hours it is pretty much done, so there is no need to be obsessive about taking it at exactly the same time each day.

If I completely space out and don't remember to take the drug for 5 or 6 hours, though, I usually only take half my dose because that way when I take the normal dose at the usual time I don't have too much overlap to worry about.

I have found that there can be significant differences in how the different manufacturers' versions of generic metformin affect my blood sugar. The version I'm taking now, the 750 mg ER pill manufactured by Teva, does not seem to be quite as slow in releasing the drug as other brands are, so I get a much stronger effect during the day, but it wears off by the next morning. Other brands last better through the night, but I don't get anywhere near as good post-prandial numbers at lunch and dinner.

Not so coincidentally, the Teva version of metformin ER comes in a compact, flecked pink pill, while the other versions are pillowy white pills that appear to involve an indigestible matrix in which the drug is embedded. I suspect that the pillowy stuff works a bit better at slowing the digestion of the drug which makes the Teva version sort of a semi ER/semi regular version. That works for me.

I've tried splitting the dose to even out the response, however, I find that if I take Metformin in the evening I end up having to get up to pee at night more than usual. Since this is already a problem for me, I prefer to take it in the morning.

Finally, both Metformin and Metformin ER are currently available for a $4 copay at Wal-mart pharmacies offering the $4 copays on selected generics.


Tom said...

I'm lucky in not having any problems with Metformin. I take 1500mg/day and 1 Actoplus tab. I'm finding your blog very informative and am thankful you are doing this. I have type 2 diagnosed December 2005. A1C then was 12.8 and last month 6.0 Eating sensibly and walking 3 miles EVERY day helps too!

Heather said...

Thanks alot, although i DO NOT have diabetes i am taking Metformin ER because my body makes WAY WAY WAY too much insulin! Metformin is the only drug that reduces the amount of insulin my body makes with out messing up my sugar. Bit Merformin er tears up my stomach if i eat too much sugar i am tired if i eat to much fat it feels like i was punched in the stomach. This is just the beginning of my second week on this medicine and i have noticed i feel better. Thanks for being so informitative!


Dobbs said...

Anyone. I been having a terrible time with Metformin. I was given 2000 MG to start. Made me fell awful. Stomach cramps.etc. Dr said to start with 500mg once a day, and increase by 500mg a day, each week until able to take 2000mg. Been taking 500mg once a day, and now on 6th day, all syptoms are back. Any thoughts. I've had diabetes for almost a year, and haven't begun to control it. Starting to get worried.Thanks

Jenny said...


Please try the technique described HERE

It should get you back into control and perhaps make it not necessary to use Metformin.

Anonymous said...

If you are having problems with the Metformin ER (generic) drug like I did, ask your pharmacy for the brand name drug - Glucophage XR. I found that I didn't have the nausea, stomach upset, and GI problems when I switched to the brand name drug. The metformin ER I was using was manufactured by TEVA. I've found other posts online mentioning they've switched to a different generic manufacturer or request the brand name drug. Try it...I bet you will feel a lot better!

Elizabeth said...

Hi Jenny - a question for you. From everything I'm reading, it seems that my doctor made a mistake with my Metformin prescription. I've been prescribed 500 mg of Metformin ER twice a day. I thought the ER version should only be taken once a day. Any thoughts? Thanks so much.

Jenny said...


Both ways of dosing make sense. Some of the ER generics are a bit peaky--they hit hard a couple hours after you take them.

If you are having trouble remembering to take the pills and want to take them once a day, call the doctor's office and make sure there isn't some reason they prescribed it this way for you and if it is okay to take it all at once.

Anonymous said...

hi, I was put on metformin for my PCOS at 500mgs a day, well after 3 weeks it seems it has lost its effect, so I started taking 1,000mgs a day... I feel sick... and nasuated...but, I am also taking clomid as well, and armor thyroid... and I have the runs all the time, could it be that 1000 is to much and I should go back to 500?

Anonymous said...

Actualy in my state the walmart price for metformin er is $9.00 a month. The regular is $4.00.

Rob said...

I reluctantly started on 500mg of Metformin ER this morning. I use the word "reluctantly" because I am not a diabetic but I am Insulin Resistant. My fasting blood sugar was 168 this morning. I workout and have a decent diet but the Dr and Dietician suggested the use of Metformin. I am generally in good shape...6'5" 245 pounds. My only real apprehension in taking the drug is the potential side-effect of lactic acidosis. Can exercise add to the possibility of this side effect? I understand this is extremely rare but it still freaked me out. I know I am probably naive and over-reacting but any re-assurances would be greatly appreciated. Thank you, Rob

Jenny said...


If your fasting was 168, you are most definitely diabetic. Anything over 125 mg/dl is diabetes and 168 is dangerously high.

Lactic acidosis is extremely rare and probably not a concern for anyone with normal kidneys.

But you need to start reading up on diabetes. Your "healthy diet" if it is a high carbohydrate diet is very unhealthy if it is giving you that high a fasting blood sugar.

For that matter, a post-meal blood sugar of 168 is high enough to damage organs.

Please visit my Blood Sugar 101 site and start learning more about diabetes.

Visit The "newly diagnosed" page to learn how to lower your blood sugar.

Anonymous said...

I'm a little curious -- my doctor has me taking Metformin 500 mg ER (XR) twice a day. I was just taking 500 once a day in the morning, and by adding another dose 12 hours later -- it seems to keep me more level -- anyone else taking the extended release twice a day? I've lost 35 pounds since January (down from 178) --so the meds with dieting and more exercise seems to be keeping my sugar levels in a healthier range.

Anonymous said...

I have read that you should not drink alcohol while taking metformin. I am taking 1 tablet a day of metformin 500 mg ER. Is there any problem with having an occasional drink?

Jenny said...

Anonymous 9/2/08,

That is the kind of question you should be asking your doctor! Only your doctor knows the details of your situation, your liver test results, and other information needed to give you a safe and accurate reply.

asnet said...

Anyone else here who thinks that generics differ or that brand is different from generics?


Suzanne said...

Thank you, I am really enjoying reading your blog.

I started regular Metformin last week, 500 mg. It gave me a little diahrrea and nausea, but not too bad. I asked the doctor about getting ER since I had heard it was easier on the system. I started taking it Thursday night (still 500 mg) as I supposed to take it with the evening meal. I got very sick and by Saturday night was having constant diahrrea and terrible nausea, plus I started getting chills and fever of 102. I think I may have had a stomach virus but I'm not entirely sure. I stopped taking the medicine and started taking it again last night. I started having diahrrea constantly and it hasn't let up except when I'm sleeping. But it's not painful at all and there's no nausea, so I'm going to see what happens with tonight's meds. I'm also taking Vasotec for my kidneys. If this doesn't work out, I might go back to the old version that seemed better for me.

I'm supposed to take two pills once my system adjusts...I can't wait :(

Anonymous said...

Thank you for your VERY VERY informative blog about Metformin.
They changed my medication from 2 metformin 500 a day to one XR a day. Since I changed the dose I have gained almost 9 pounds, could that be from the medication change???
Thanks for your help

Jenny said...


Both doses you cited are low enough that they might not have been enough to have much of an effect. Most people need 1500 mg to 2000 mg to see a true impact.

In any case, Metformin shouldn't promote weight gain. Many of us find it works the other way and the research data suggests that.

Ask your doctor about upping the dose and cut back significantly on your carbohydrate intake and that might help.

Anonymous said...

I just started taking Metformin ER 500mg. I take two at supper time. I don't have an appetite at all, I wonder what I could do about that. I know I suppose to eat six small meals a day and I barely get in three. Help

Lisa said...

I have PCOS and my fasting blood test came back high. I'm overweight too. My DR. placed me on Metformine 500mg twice a day with morning meal and one for dinner. I'm going to pick up my RX later today. I'll keep you updated tomorrow, as I am taking my first pill with tonights dinner.

Lisa said...

I took my first pill las night and I didn't feel well. I sort of felt hot. Not fever like, but I felt like my body was warm. I woke up this morning and had the runs. I just took my 2nd pill with breakfast. I ate a banana and watermelon. Should I est protien? I'm trying to eat better.

Jenny said...


The symptoms you describe are completely normal, and if you are patient they should be gone in a few days.

Re the banana and watermelon. These are fruits very high in sugar. I have never met anyone with Type 2 diabetes who could eat bananas without a high blood sugar spike.

Please try the technique you'll find on this page and test after you eat, lowering the carbohydrates in your food until you get safe blood sugars. It will really help you avoid complications:

How to Get Your Blood Sugar Under Control.

Lisa said...

Thanks Jenny! I guess I have alot to learn as far as eating healthy. Fruit is healthy, but I can't eat it? This is all so new to me. Do you reccomend a website that shows what I should or should not eat having type @ diabetes? Thanks!

Jenny said...


What makes a food healthy for someone with diabetes is how high it raises your blood sugar.

Berries have little carbohydrate in them, so they are much healthier than sugary fruits.

Here is a page that might be helpful:

A Diabetes Diet is Different From A Weight Loss Diet

Anonymous said...

My Doctor just put me on Metformin ER 500mg once a day from regular Metformin 500mg. I have been on the ER for 2 days and my blood sugar has increased when I checked it 4 hours after I ate,, 134 after I ate 2 hours to 152 4 hours after I ate. What does that mean? Is the ER not working?

Jenny said...


Give the Metformin 2 weeks and if you don't see improvement, call your doctor and discuss the problem with him.

Tamara said...

I've read all the posts and I have a dosage question I don't believe has been discussed yet. I am what is best described as a pre-diabetic, i.e., I have some borderline indicators but nothing officially diagnosed. I've been taking 500mg of Metformin twice daily and at my request, my doctor has switched me to Metformin ER. However my prescription is to take 2 of the 500mg ER tablets once daily. Isn't this double the amount I was taking previously? I thought that the half-life of the drug meant I was getting a somewhat constant 500mg dosage all day long, and it would seem now that I am getting 1000mg all day long.

Jenny said...

The 500 mg dose of Metformin in either form is too low to be effective in most people. The dose you are on now is still a very modest dose. Most people with diabetes don't see much impact until they get up to 1500 mg.

Are you seeing different blood sugar results? Too many side effects? If not, then don't worry about the dose. The non-ER is more hard hitting than the stuff that is spread out through the day and if your goal is to lower post-meal blood sugars, a higher dose might be more effective.

Tamara said...

Thanks for the info Jenny. Since I've yet to be diagnosed with diabetes, I imagine that's why I'm on such a low dose. I also have not been instructed to measure my levels outside of when I get tested at the doctor, so I don't have any idea how the new dosage has affected them, but I'm now considering purchasing a meter to keep track of things.

However, I've been on the 1000mg ER for 48 hours now and it's had some nasty side effects, nausea, headaches, stomach pain and lightheadedness. I am taking the generic form by Caraco Laboratories. At what point should I start to consider switching manufacturers, dosages, or back to a non-ER form? One post cited the adjustment period of being only two days, another up to two weeks....Thank you!

Jenny said...


Give it two week. Many of us find that we don't feel good the first week or two.

The ER form is milder than the other, and usually the stomach symptoms do abate.

Anonymous said...

Great info Jenny, thanks. I am on 1500mg of XR per day for PCOS. I've been taking it for a couple of years without incident, but have read that it can sometimes be more effective to spread out the dose, even with XR. do you know how true this is? also - i started spreading the doses out with the OK from my doc, 750 in the am and 750 in the pm - and it's caused me stomach upset the past couple of days since i started doing this. i didn't change the dose, just spread them out. its kind of annoying to be getting the upset stomach now - but hopefully my body will adjust after a few days?

Jenny said...

Usually splitting the dose decreases the stomach problems, unless perhaps you were taking it at night before and now are taking part before meals? Maybe cutting back on carbs might help. Metformin may block carb digestion and that may be causing the stomach issues.

But it is hard to say.

kp disorganized said...

what are your thoughts on splitting up XR doses in general? if it's 1500 all at once or 750 twice a day .. i read somewhere you saying you tried to split them up.

Jenny said...

My experience with splitting the dose was that taking any Metformin at night seemed to make me have to get up more often to pee, so I stopped doing it and took it first thing in the morning.

But I hear from people who split and people who don't both of whom report that it works. I suspect that after a few weeks when the dose is established in your blood stream it doesn't matter when you take it as long as you are consistent.

Anonymous said...

Lisa, I also have PCOS and it is very different than having diabetes, its ok to eat sugars and other foods, like bananas, which a diabetic would have a hard time eating without their sugar levels soaring. My sister is diabetic and we both take the same doses of metformin but for different reasons... Most people with pcos are taking metformin to control insulin rather tan blood sugar... here is a great site for people with pcos and questions about the medications...
there is great info inside the message board forums....

moonlight said...

I have been taking Metformin 500 mg twice a day for an year and for the last six months I have been using Metformin 500 mg once in the morning. Yesterday my doctor prescribed Metformin ER along with Glimepiride and Pioglitazone. I have reservations about Pioglitazone for the side effects it can cause. It is a class of drug along with Rosiglitazone. Like other thiazolidinediones, pioglitazone can cause fluid retention and peripheral edema. As a result, it may precipitate congestive heart failure (which worsens with fluid overload in those at risk). It may cause anemia. Mild weight gain is common due to increase in subcutaneous adipose tissue. In studies, patients on pioglitazone had a slightly increased proportion of upper respiratory tract infection, sinusitis, headache, myalgia and tooth problems. Kindly advice can I go ahead with these medication

Jenny said...


I'm not your doctor so I cannot advise you about your medications. What I do is give people information. After that you have to talk to your doctor about your concerns. If your doctor is too busy, perhaps there is a nurse practitioner in his practice you can speak with. If no one is responsive, talk to friends with diabetes and see if someone can recommend a doctor who communicates better.

moonlight said...

hi jenny,
thanks for the reply. yeah you are right. the problem with doctors is they say every drug has its own set of side effects. you got to look at the larger picture. may be they are right. trying to clear my own confusions in my own way.

Krista said...

I've been on metformin er, 1000 mg/day at dinner, for 8 months now and just recently went up to 1500 mg/day because I seemed to lose some of the BG control. In the first 3 months, my A1c dropped from 7% to 6.5% along with 20 lbs weight loss. In the next 5 months, my A1c crept up slightly to 6.8% (weight stable) so my Dr. increased my dosage. I'm having some intestinal problems with the increased dosage but hope it will wain with time. Jenny, do you know the metabolic half life of metformin er? Or in other words, how many hours after taking a dose does your blood levels of the drug peak?

Jenny said...

I'm not certain what the actual metabolic half life is. I have noticed different peaks with different generic versions of Metformin ER.

If I forget to take it, I can see a small difference in my blood sugars after meals with carbs. But it takes about 10 days to completely clear out of my system.

That's me, though. I'm not sure it is a one size fits all thing.

Anonymous said...

My Endocrinologist has me on Metformin HCL ER 750 mg (taking one and one half pills) 2 times a day. The bottle has precautions about breaking or crushing the pills and the pharmacy warned me not to break the pills in half. I am now wodering what the danger is about if I do break them in half..I have been doing this for 2 years now.

Jenny said...

The problem with breaking Metformin ER in half is this:

The Extended Release feature of the drug is caused by it being encapsulated in some kind of matrix that digests slowly as it passes though your digestive tract. If you cut it, it will digest faster, so you no longer get the slower, longer action.

If it is working well for you and you aren't feeling like yo uare getting an overdose (which trust me, you would feel--I've done that) it probably isn't an issue.

Anonymous said...

what are the symptoms of an overdose? Only thing I experience on a regular basis is diahrrea.

Jenny said...

The symptoms of an overdose, for me at least when my doctor mistakenly prescribed one, was feeling extremely unwell throughout my body.

Diarrhea is a standard metformin side effect but one that is often much better with the ER. You probably should stop cutting them and if dose is a problem get your doctor to prescribe the right size dose. Metformin ER comes in various dose sizes.

Also, you can avoid some of the diarrhea with metformin sometimes by cutting back on the carbs as unfermented carbs hitting the gut is one cause of the diarrhea.

Anonymous said...

I have PCOS and am taking 500mg 3x a day on regular metformin. How much should I take of Metformin ER and how often. I no longer have insurance and go to a free clinic that doesn't know anything about this, but will work with my suggestions.

Jenny said...

We are not doctors here so we cannot tell you what dose you should be taking. It would depend on many things, including some lab values.

If that was the dose you were prescribed in the past and nothing has changed in your health, you probably are safe continuing with it. That is a very standard dose and many of us find that adding extra metformin after taking 1500 mg does not make a significant change in the effect it has on us.

The Bro said...

HI wow what a great gem I have found here I can see I will spend lots of time reading all the comments.
I am on 1000 mg Metformin and seem to suffer lightheadedness some 'tummy upsets' (read into that what you will!! lol)and headaches.However has anyone else had any more unusual mental symptoms? Im curious because since starting Metformin (almost 3 months now) I am very emotional,nervous and have a lot of anxieties/paranoias.Im normally a happy, mellow person and this is not me.Im also very angry sometimes. Please someone tell me they have had a similar experiences I dont want to think I am going crazy!!My initial count was 19 (yeah bad, bad, bad) but now down to 10 (better but not great I know.)Dr told me come back in 3 months so will go see him soon but he isnt great to 'talk' to so hoping to find more help here.Thanks Janette from Australia

Jenny said...


I have observed that Metformin has an impact on female hormones, which may have something to do with the mood changes you are experiencing. It is often prescribed to women with PCOS to lower testosterone, too.

It is also possible that dropping your blood sugar dramatically is causing mood changes for some reason too. Avoid the temptation to take antidepressants for these changes, though, as they have been shown to worsen blood sugar control in some people and often are no better than placebo.

Based on my experience, if you wait it out for another couple months the mood issues should calm down on their own.

If you are in the perimenopausal period, it is also possible that you are starting into menopause which would also cause similar hormonally mediated moods.

moonlight said...

i am on metformin for the last one year and on metformin ER for the past three months. I have been experiencing severe mood swings especially towards the evening. Here in India they prescribe Metformin 500 mg ER along with Pioglitazone 15 mg and Glimepiride 1 mg, in single dose. that is what i am having in the morning. I don't experience any stomach upsets but mood swings are there. I am having my tablet just before i take my breakfast. I wanted to know how much time before i should take a tablet before breakfast?

Jenny said...


Because your pill is a combination of so many different drugs, you had better ask the doctor who prescribed it about when to take it.

Romaida said...

I started taking Metformin for PCOS a week and a half ago. My dr had me start at 250mg at night since I usually get all the side effects from medication. That wasn't too bad. I did get a little nausea and diarrhea but I could tolerate it. A few days ago, I started taking the 250mg twice a day and boy has it been horrible! I get sooo tired! I start feeling lightheaded, bloated, feeling warm and have had cold sweats and a little weakness. Has anyone else had those side effects? Would taking 500mg at night be okay instead of 250mg twice a day? Thanks!

Jenny said...


Give it a week or two. The side effects often calm down.

If not, ask your doctor about using the ER (extended release) form which many of us find much easier on our digestive tracts.

vesuvana said...

I've just started metformin ER 750mg. Next week I go up to 2 tab a day. The doc prescribed name-brand glucophage XR, but Walmart gave me generic metformin ER by Barr which was still $90! I am worried about the side effects making life miserable during the day. I am a college student so I can't just get up and go to the rest room when I want and there is no privacy anywhere on campus, if I get gas, etc. So I have 2 q's:

Can I take something like phazyme or gas-x along with metformin?

Can I take it at noon with my lunch meal (instead of at dinner as prescribed)? I figure by the time the medicine hits my system and starts giving my any side effects, I'll be getting done with my school day instead of being incapacitated all day long.

Jenny said...

That's an awful lot for the Metformin. Call around until you find a supermarket or pharmacy that offers cheap generics. The metformin XR is a generic.

You can take it any time of day, just leave 24 hours between doses. I take mine around 2 PM lately. It is then strongest at dinner and has a bit more impact on fasting blood sugar.

The gas etc should calm down after a few weeks, it often does.

vesuvana said...

Thank you. So far the worst side effect is the terrible heartburn. Is it ok to take pepto bismol or pepcid while taking metformin?

Jenny said...

I have experienced the heartburn associated with Metformin. You can take any antacid, but in my experience the best solution was to take Prilosec for no more than a week.

However, if pepto-bismol works, go for it. It won't affect the action of the drug.


My doc started me on 1000mg of regular Metformin in July. My A1C was 6.2 & AM readings in the 120's. Through the years since a surgery that took half of my pancreas, my sugar has been creeping up so it was time to do something. At the end of 2 weeks, I started to get readings in the 115 area, then it started going UP. I am now waking up with readings of 140 & higher. When I saw the doc in early September, he said wait till December & we'll see. WHY WOULD SUGAR GO UP RIGHT AFTER STARTING METFORIM? Any thoughts are greatly appreciated. This is a great site, by the way.

Jenny said...

I don't know why your blood sugar would rise after taking metformin--that isn't a reaction I have ever heard of.

Is your doctor an endocrinologist? If not, find one, because family doctors are woefully ignorant about anything having to do with diabetes and with half a pancreas your situation is more complex than a that of a Type 2. And more likely to need insulin.


Thank you for the reply, Jenny. Yes, the doc is an endocrinologist. Your rely didn't surprise me as I could find nothing about circumstances where the levels would rise. I suppose I wondered if it was indicative of Metformin being the wrong type drug & triggering a reverse reaction. Oh, forgot to mention I am not overweight, walk at least 6 miles a day & use weights: so lack of exercise shouldn't be an issue. Anyway, thanks again.

K A said...

I have just begun Metformin once a day.. I have
a Hiatal Hernia and GERD. I take my Metformin at night and find no amount of Perlosec or Tums or Peptid AC are calming the sever heartburn and at night the GERD ( reflux in sleep) Any suggestions on how to survive past the 2 week adjustment. I have been on a low cab for 3.5 months prior & reduced my fasting BG to 10l from 126 don't have a recent A1C test last one was 5.6 2 yrs ago Karen A.

Zatzzie said...

Hi Jenny,

What about the phthalate content in many extended release drugs? This could be a bad idea for women trying to conceive or already pregnant.

Jenny said...

Zattzie, That is an interesting question and one I had not seen discussed before. If it is a concern, ask your pharmacist about the other ingredients in the particular brand the pharmacy sells. I haven't read anything discussing this issue, so I don't know if it is a concern for people with diabetes.

Barbrie said...


I have been on regular Metformin 500 twice a day for 5 years. My average tests run from 98 to 134. Yesterday I started a new perscription of Metformin HCL ER 750 twice a day.

Though I eat basically the same diet each day this morning my sugar was 158, took the pill with breakfast and 2 hours after it was 167. Took one with supper and tonight my test was 161.
I have no clue what is going on. Is this common when you first start the ER drug?I do go for my A1C next week.

Thanks for your input,

Jenny said...

Barbara, Because the ER is slow release, it might take a day or two to kick in. If you aren't seeing your usual blood sugars by the end of the week, though, you probably should talk to the doc about it.

Ann said...

I'm on metformin 500mg(Obimet ER) twice a day after meal for about 6 weeks now, I haven't reduced even an ounce. I am doing cardio- excerecise everyday and I'm watching my intake too. Im so confused and worried.

Jenny said...


That's a low dose. Many people need a higher dose to see an effect.

If a higher dose doesn't have an impact, you need to see a skilled, preferably young endocrinologist to find out what might be going on.

Ann said...

Thanks Jenny :)
I gotta apt with my RE.

Shannon said...

Hello, I have been on Metformin ER 750 mg two times a day for a couple of years for PCOS, recently the pharmacy switched me from the white pillowy pills to the pinkish Teva pills and I am having a really hard time digesting them, I don't normally have the diarrhea or stomach cramps but since taking the Teva brand I have a really hard time swollowing them as they always feel like they are stuck in my throat and when I do get them down I have really bad stomach cramps right away and diarrhea and I can tell the pills are not digesting. Has anyone else had this problem? I am considering going to ask the pharmacy to change my pills back. Thanks

redroses said...

i have been prescribed by my fertilty doctor metformin ER 500 mg twice a day. does this seem right? can it be taken twice? or is it better to take it once a day

Jenny said...


With the ER it doesn't matter if you split the dose or not because it slowly releases over a period of about 24 hours.

It's common to start people at a lower dose and then raise it after they get used to it, but I don't know what the appropriate dose is when it is used for fertility (usually in PCOS). You should ask the doctor who prescribed it about this.

Jenny said...


I don't have problems with the Teva ER but I have noticed that it seems a bit "peaky" i.e. it's stronger a few hours after I take it. I like this, as I take it to coincide with dinner, but since it's causing you problems you should ask for a different generic and if your pharmacy won't supply it, call other chains until you find one that will. Each pharmacy seems to sell a different brand.

Patsy said...

I began taking metformin ER 500MG 12 days ago. The side effects were minimal. A little nausea but nothing bad. Suddenly in the last 2 days I've had dizzy spells. Tonight I woke up at 2 a.m. and my head was spinning very fast while still lying on the pillow. It woke me up. It continued to spin for up to ten seconds and that was scary. I was afraid to get up for fear I would crash into something. Eventually, I got up slowly, and have done okay but I don't move my head suddenly.

I don't see this side effect from anybody else here in the blog. Is it a possible side effect of Metformin? Some say they feel dizzy but they haven't mentioned it being this strong.

Also, I am instructed by my doctor to test my glucose twice a day - upon waking, and 2 hours after a meal. I have not been diagnosed as diabetic but my A1c was high enough that diabetes seemed imminent so I went on a strict diet control and kept it under control for five years.

Then I got a severe and crippling pain in my neck that required two weeks of frequent visits to the chiropractor to get rid of. During the two weeks following the onset of the neck pain my glucose shot up pretty high and it never went back down to pre-pain levels.

So my doctor prescribed Metformin. I am seeing some reduction in the numbers but not what I had hoped for. I have noticed that when I exercise and fast a bit longer than usual it drops below 100 but comes back fine when I eat something. Generally, since starting Metformin, when I wake up in the morning it has been around 115 to 127 and that seems high to me for fasting. Prior to Metformin, but after the neck pain began, it was as high as 160 once in the morning.

3rd question: How can I test my meter, which is five years old, to be sure this problem is not a meter problem? Do they wear out yet still work, leaving you with bad numbers?

Thanks for all the information in advance.

Jenny said...


The dizziness you describe sounds like vertigo. It is usually caused by an inner ear problem, often a virus. I have never heard of it being caused by metformin. Call your doctor to ask about it.

500 mg is too low a dose to have an effect on blood sugar for most people. It usually takes 1500 mg/dl.

Replace your meter's battery or buy a new one. They do go bad over time. A fasting blood sugar over 125 mg/dl is officially diabetic, and if after updating your meter you still see sugars that high take them seriously. A real 160 fasting would be a serious problem.

poopsmcgee said...

I have been taking Metformin ER 750, 2 tabs once a day at bedtime. I recently noticed that the medication is passing through my system virtualy undigested, appearing whole, yet decidedly waterlogged upon excretion. I'm not sure if the meds are even getting into my system this way - has anyone else experienced this phenomenon?

Jenny said...

if your blood sugar is improving you're getting the medication. The prescribing information describes exactly what you've observed but explains that is only the matrix being excreted. The drug should have been absorbed.

Ryan said...

Wow.. such good information! I've been having problems similar to the previous poster who talked about the neck pain. I've been taking Metformin ER 1000 mgs twice daily. It's been making me sick as a dog!! The best way I can describe how I've been feeling is carsick. If it was just diarreha I could handle it, but I've been getting terrible headaches that seem to originate from the back of my neck. My shoulder and upper back muscles seem to be sore also. And the nausea is terrible. I'm wondering if I could have lactic acidosis? I don't think I have kidney probs. It just doesn't seem normal to be this sick. It's severly impacting my life. I've had to miss 3 days of work in 3 weeks. I work in a call center and the other day I actually threw up while on the phone with someone! After reading the article here, I'm wondering also if taking it twice a day could be my problem. I'm going to try once a day tomorrow but I'm falling back to 1500 mgs for a while. I'm wondering if anyone has found a suitable alternative to Metformin...I'm PCOS and trying to get preggers so my doc wants me on Met, but I'm not sure I can make it like this. I've tried Januvia before and found, rather strangely, that it actually RAISES my blood to 175 fasting. Anyone else experience this?

Thank you for all your wise words Jenny! I truly feel lost and find sometimes doctors just throw RX's with out really trying to find the best solution for you.

Jenny said...


Lactic acidosis is supposed to be extremely rare, but your symptoms are serious, whatever their cause, and you should call your doctor about them.

jacque k said...

Hi Jenny,

Such a great post about Metformin--I keep coming back and always find something new and helpful.

I filled a new prescription for metformin ER 500 mg today at my regular pharmacy. Instead of the usual long white tablets, these have a similar shape but a glossy coating. Found out they're from Teva. Do you know if these are the same formulation as the pink ones?


Jenny said...

The only thing that might change is if it is an extended release version of Metformin, the speed with which it dissolves might be a bit different. My experience with some Teva Metformin ER is that it peaks (i.e. is at its strongest) a couple hours after you take it where other brands are a bit more uniform. I liked that as I could time the peak to coincide with dinner.

Cindy said...

I am a diabetic who took Actos for over 15 years along with insulin. I am bad and do not follow a diet nor test, mostly because I just can't afford another script even if just a co payment. Anyway my weight has gone up at least 10 lbs a year. I had to do something so I asked my Doc to switch me to Actosplusmet. But found it had an even higher copay so opted for just Metformin as I had heard it helped with weight loss where actos caused gain. I am taking 2 500 mg tabs twice a day (I found I saved 4 bucks for 90 day supply by splitting into more smaller dosage pills at walmart)The heartburn, indigestion and runs has about made me go back to actos. The thing is it doesn't do it all the time. But with the way I work I cannot run to the bathroom constantly. I tried with Dr blessing taking 4 doses a day to make it a lower does but it did not seem to matter. Some days one will kill me all day and some I can go all day with only minor problems. I have lost about 12 lbs, but told my dr I think the only reason it helps with weight is because it makes you feel too sick to want to eat. I don't understand why it seems that the ER helps some and not others. I may call my doc and see about changing when I need a new script filled. Also if Metformin controls insulin, should I be taking insulin with it? I just switched to Levimir a long acting insulin last fall. In spite of eating less my A1c has gone up.I know there are diet drugs that work by clinging to fat and removing it rather quickly, hence diahrrea. Is this drug similar? Are there any other diabetic drugs that aid in weight loss rather than gain? Thank You, Cindy

Jenny said...

Cindy you ask a lot of good questions--more than I can answer in a brief comment. You can read about exactly what metformin and other drugs do on this page:
Drugs and Food Click on the individual topics and read up about the various drugs. That should help you understand what the drugs actually do better.

Metformin makes your body able to use insulin better, but if you aren't making insulin, metformin won't be able to create it. So don't stop your insulin unless you start going very low.

The Woo said...

The simple answer is: Some people are affected by side affects WAY more than others. Everybody is different....even when it comes to the whole diagnosis of Diabetes type 2. For instance, I have been "borderline" my whole life then stepping over the border just a year ago....I can barely take metformin. It about causes me to go in to the hospital from the gastric problems. My wife, on the other hand, was diagnosed with SEVERE diabetes presenting no symptoms save for some tiredness once in a while. However, her very first number when checked four months ago was 560 (yes five sixty) and the doctor was amazed she wasn't being thrown into a diabetic coma hospitalized. !! And, the better news for her, they started her on metformin...2000 mg x2....and her numbers are now down below 100....several times dipping into the 80s. Plus, she's lost 20 lbs and has ZERO side effects. Lucky girl! ;)

Madhuri said...

Thanks for the very informative blog! I have a question about timing. I'm taking 1500 mg/day of Metformin ER. I take one 500mg pill in the morning before or with breakfast and 2 500 mg pills in the evening before or with dinner. If it's ER, does it matter at all when you take the medicine? Is it best to take it 30 min before a meal, or with or after the meal, to get best benefit? Also, do you know what exactly is the problem with drinking while taking it? I was under the impression that alcohol can lower blood sugar, therefore possibly increasing the chance of having very low blood sugar. But is the problem also that both alcohol and metformin are metabolized by the liver, therefore putting the liver at risk? I often will have a glass of wine before dinner, and since I also take the metformin at the same time, I'm wondering if there's any problem with taking both at the same time before a meal. Thanks for the info!

Jenny said...

Madhuri, I've discussed timing metformin doses in a recent post:

The problem with alcohol is the shared use of the liver. My doctor told me one drink or so was fine. The problem comes with heavier alcohol use. Many people aren't honest with their doctors (or themselves) about how heavily they drink, hence the need for caution.

Herb said...

Hi; thanks for the great info.
My doctors office made an error, i have been taking the ER version @500Mg 2X per day, the new script, was for the regular version @500mg.
Could I take both, i.e. standard during the day and ER at night?
Thanks for any advice you can give me. Herb F

Jenny said...


That is a question you should ask your pharmacist.

Vito said...

Additional insights,
I was diagnosed in 2006 as type 1 initially and let me tell you it was no fun injecting insulin. However, my primary care Dr. was wrong. I started regular visits to a Endocrinologist and he put me on Metformin 1000MG twice daily after some analysis. That changed everything because he said you are not type 1 you are type 2. my A1C was 6.0-6.5 until I started taking Avandamet which put my A1C down to 5.5-6.0. Last year I started taking Metformin SR 2000MG a day because of the cost of Avandamet that went through the roof and no issues taking the Metformin. Unfortunately, the Endocrinologist has gone to a diabetes center far away so I don't have the benefit of seeing him anymore and he was superb. Fortunately, I've found an excellent primary care that is very good with diabetes.

The point I am trying to make here is, if you can go see a endo do it you will thank yourself for doing so. Unless you feel you are doing well but it still won't hurt.

About me,
I am about average build 5'9 160 lbs, in my mid 40's and I have a pretty healthy diet but it could be better. I have always had very good control from the start because it was a life shocking change.

Moreover, when you cook stay away from veg oil use olive oil and only use fresh veggies and meats think about your heart. Stay away from saturated fat, the more protein the better. My diet is basically protein, fiber, and pasta in moderation (I know high carbs).

My doctor pointed this out to me and the other thing you need to watch for is potassium levels which will create problems such as the gout. Believe it or not, a lot of things we eat has potassium which is used for preservation hence shelf life.

Exercise is important as well so don't be a couch potato even if it is a walk around the block, just do it.

William and Cathy said...

Hi, I have just been put on metformin ER 500mg.I am not a diabetic my blood sugar highs are only 105-110. My doctor has put me on this med. b/c of the way my body stores sugar. He has put me on 1 tab. 2 times a day for 7 days and then 2 tablets twice a day. Wow will this affect my sugar levels. Will they drop to low? I am overweght(obese) and this is another reason he has put me on this. I am 5'5" and 230 lbs. I also have IBS so hoping this won't make that bad. Any advice???????

Jenny said...

William and Cathy, It sounds like you have a good doctor. Your fasting blood sugar is significantly higher than normal, and unless you start working on lowering it, it might very well climb into the diabetic range. This doesn't happen gradually, but very quickly after years of slow deterioration.

I would urge you to read the page How to get your blood sugar under control"

Blood sugar is a lot easier to fix in the early stages of decline than it is later.

Metformin will cause far fewer gastrointestinal symptoms if you cut down on your starches and wheat. In fact, many people find their IBS goes away if they eliminate wheat.

wavelock said...

Hi Jenny,
i am 5'3", 124lbs, Male 43yr old , my doc said i should not take metformin because i am not overweight therefore not insulin resistance.
is that true?

can a person with normal weight be a insulin resistance?

How can i know if am insulin resistance?

Jenny said...

Usually people of normal weight aren't insulin resistant, however, that isn't always true. I know quite a few people with Type 2 diabetes who eat low carb diets and are normal weight but who are still very insulin resistant.

The definitive way of telling is to inject some insulin and see how much it takes to lower blood sugar. An insulin resistant person will need perhaps 30 units to cover a meal where a non-insulin resistant person would need only 3.

Barring that it's hard to be certain. Have you been told you have the antibodies that diagnose LADA (slow autoimmune diabetes)? If not a trial of metformin might be worth a try. If it does nothing you may very well be insulin sensitive. If not, you may get better blood sugars

wavelock said...

Thanks for the info.
since i am of normal weight and if I take metformin, will i further loss weight?( but i want to gain a little weight.)

Jenny said...

Metformin will cause a few pounds of weight loss that aren't fat, but seem to be the weight of glycogen stored in your liver (the same weight you lose on the first days of a low carb diet). That weight comes right back if you stop it.

After that you shouldn't lose weight unless you cut your calorie intake. It makes your insulin more efficient--insulin sensitive Type 1s who use metformin need to inject less insulin.

wavelock said...

Can metformin harm our kidneys?

Jenny said...

Metformin may not be safe if you have been diagnosed with actual significant kidney disease as it is eliminated by the kidneys. But it doesn't damage the kidney.

You can learn much more about metformin HERE. I urge you to read it.

j said...

Thanks for write this great column & all replies to this thread.
I Have PCOS and my Dr. Prescribed me 1000mg of metformin, and i couldn't take it (i was spending most of the day sitting on the bowel...) so i went down to 500mg and everything was perfect (just a very slight diarrhea) and i lost about 10 pounds (which was great!)
Then I got pregnant and continued till 3 months into my pregnancy.
Three weeks ago i started taking it again but this time i am taking 750mg ER {from Teva} and i'm not having the any side effects, does this mean that it's not having an effect on me or that it's working much better and thats why i'm not having any diarrhea (i don't mind a slight discomfort if it will help me lose weight :)
P.S. i don't know my current blood sugar level to be able to test the difference
P.P.S. last time i took the white oval shaped tablets, dont know which company or if it was ER or standard (i took 1 500mg pill once a day)

Jenny said...

J, This time you are taking the ER form this time, which is easier on the digestion. It should still work well for you.

pammy said...

thanks for all the info. I was diagnosed in OCT 2010. was prescribed Metformin500MG ER. Took my first dose yesterday. I was worried about my kidneys, liver and dying. I lived. Jen-

C said...

I have a question. I was 500 mg Metformin twice a day and missing the second regularly. I asked to change it and the Dr. agreed moving it to 1000 mg ER. However the pharmacist filled the prescription with 2 500 mg ER. To my mind this is not the same. Rates of release etc., and strengths at release would vary withthe net effect not being the same.

Jenny said...


Two 500 mg ERs would be about the same as two 500 mg doses of regular metformin taken twice a day.

Dolores said...

I was on metformin XR for 2 months and doing fine... but I got my refill today from the pharmacy and it was regular metformin (round tablets) Is this a mistake on the part of the pharmacy or are the two interchangeable? I take it once a day with dinner.

Jenny said...


Check with your pharmacy. They may have changed brands. But if it is regular metformin it IS a pharmacy error and they need to correct it. The regular won't hurt you, but it can cause stomach distress and needs to be taken in 3 doses, one at each meal.

BLOGDE said...

I've just been switched by my doctor from the er version once a day to the regular version twice a day. Until I stumbled upon this web site I had no idea where my mid to late afternoon killer heart burn was coming from.

So, if the er version gave me some very painful heartburn, I'm sure not looking forward to what the regular version can do!

Nice blog! I shall visit again.

Marty said...

Last November my doctor started me on Glumetza 1000mg (extended release). My a1c has dropped from 9 down to 6 over the past four months. He is now moving me to a lower dosage of Metformin. He has me taking 1 500mg Metformin HCL tabs twice a day. This seems strange to me since I'm still taking 1000mg total per day. When I asked the doctor and the pharmacist about this, they both told me it was because Glumetza was extended release and Metformin was not. Does this seem strange to you guys? It seems to me like 1000mg of one should be the same as 1000mg of the other.

Jenny said...


I'm baffled as to why your doctor would take you off of a regimen that made such a dramatic improvement in your health, especially as it would be helpful to get your A1c down into the 5% range. (The arguments that lower A1cs are dangerous don't hold up for people using diet and metformin.)

The top dose of regular metformin is a bit higher than for the extended release but I'm not sure if that is because the one is less powerful than the other. The regular is more likely to cause digestive upsets.

mermaid2 said...

I am new...well we all have to be new once :) This winter I was diagnosed with Type 2 Diabetes. I started out on Metformin 500 twice a day, it was not helping and I felt sick like so many of you. He (the doc) now has me on Metformin ER500mg. I take it in the morning after my home-made "breakfast cookie". This cookie recipe is regular oatmeal cookie recipe only I remove some white flour and add a scoop of protein powder and replace white sugar with stevia. I am feeling sick to my stomach and week. I have fibromyalgia and take Oxycontin so no diarrhea but would have that if I was not on oxy. Here is my question and problem. My husband is sure that I should be eating more than one cookie (oh this cookie has lots of dried fruit) I look at the cookie as eating a bowl of oatmeal so I think I am eating enough. Any thoughts about what to eat before taking metformin? I really have not read the answer to this question. I started drinking milk with my cookie so that should help but my stomach is upset for 1/2 a day and I am unable to get any energy. There is a lot going on with me so I know that any suggestions will be weighted on my issue's. My blood sugar is still all over the chart. I also am not a big eater and have lost weight.

I am 66yrs old and weigh 145 and
5 ft 6".

1. what is best to eat in the morning? Is my cookie enough
2. Is taking my metformin ER in the morning the best time to take it?
Thanks in advance for your help.
Carol in Idaho

Jenny said...

Carol, Oxycontin will slow your digestion way down, and that intensifies the stomach irritation caused by metformin. Milk is very irritating to the stomach, contrary to what people believe. So are starchy foods like oatmeal if they sit in the stomach for a while. You might try eating a mostly protein breakfast or one with a mix of protein and fat and see if that's any better. And don't take the metformin until after you've had your breakfast. It is really hard on an empty stomach. Just make sure that you leave 24 hours between the doses.

Read the page about how to lower blood sugar which you'll find HERE. If your stomach empties slowly you may have to test your blood sugar several hours after eating instead of just an hour afterwards to find the time when your blood sugar is highest. But once you can find when it peaks, you can start cutting back on the starches and sugars until you start seeing your blood sugar coming down.

mermaid2 said...

Jenny, thank you for all your information...I did take the diabetes class at the local hospital and frankly I have learned more important facts and "how to's" in your blog than the two week class.

old cyclist said...

I was diagnosed as a diabetic two months ago. I now take three 500 Mg tablets of Metformin one after each meal and 1 50 Mg tablet of Januvia. My blood glucose readings are good. I occasionally experience loose bowels every two or three days and when it happens it is usually after lunch. My main physical activity now is cycling 20 miles on Saturdays and 20 miles on Sundays. I am concerned about being caught on a country road miles away from my car with a desperate urge to find a bathroom. It hasn't happened yet. I would like to go on longer bicycle rides. Do you or does anyone else have advise about me possibly NOT taking the Metformin on the mornings that I cycle? What about Metformin ER?


Jenny said...

The Metformin ER can be a lot gentler on your digestive tract, though this can vary from brand to brand with the generics, so trying the ER and if you still have issues, trying a different brand might be helpful. With the ER usually you can time your dose to take it all at once and if you do get digestive issues, you can slide the time you take it so that they occur when you're likely to be home. But you may not have the same problem.

Also, cutting back on your carbohydrate intake can limit the digestive issues.

That said, the combination of Januvia and Metformin can really screw up your stomach, so if you must take Januvia (which works well, but which I don't think is a safe drug--see explanation HERE) take it a few hours before you take the metformin.

Kath said...

I've been taking Fortamet 1000 mg for almost 2 years, and because I'm in the donut hole in my RX coverage I can't aford it for the rest of the year. As it was my co-pay had gone up to $65 and now it would cost me $120. I've tried to get help to pay for it but there is none and I don't qualify for Medicaid. So my doctor gave me samples of Glumetza ER. The pharmacist told me the mertformin ER was the same. I had no side effects from Glumetza so I got a RX for metformin ER 500mg 2 once a day. On the first day I had a little upset stomach, but on the second day I had the runs and very bad pains in both upper and lower tracks. I didn't take any last night with dinner and my morning results were 111. I'm thinking of only taking one 500mg tab and see if I can tolerate it. Then build up to 2 tabs.

nanditha said...

I am a new entry with diabetes for almost 12 years now but coz of my accalasia cardia and 3 to 4 times dialatation of it somehow metformin or the other oral drugs were not tried on me now I am on sitagleptin and metformin combination 500 mg in morning and the same in evening,I have a doubt that metformin in my case won't work or some diabetic people don't respond to that if so please tell me why?
Nanditha my email is

Jenny said...


Metformin does not lower blood sugar if the reason the sugars are high is that your body isn't making insulin. In that case, you would need insulin.

Metformin also might not work if the dose was not high enough. Combination drugs may make it impossible to dose metformin correctly without delivering an overdose of the other drug in the pill.

If after several weeks you are not seeing a significant change, tell your doctor and ask why you should be taking this expensive drug combination. Especially since Januvia has many side effects, some serious.

CHARLENE said...

Hi my name is Charlene.I am at the moment on glucomed and now my house doctor put me on metformin 850.Since i am on metformin i have a runny tummy and feel very weak when i drink the tablets is it possible that i cen change to glucophage xr 1000.

Thank you


Jenny said...


Give it a week or so to see if your body can adapt. The gastro symptoms often pass after a couple days. If they don't, then contact your doctor about switching to the extended release form.

CHARLENE said...

Ok Jenny will do so. I will come beck to you

Robin said...

I began METFORMIN ER HCL 500 about 3 months ago 2X a day with food.
I haven't waited 24 hours between pills as didn't know I should.
I've had some side affects, but bearable as I want this to work.
MY sugar was up to 116, from having been normal in the past, so I'm hoping it will get lower again.
I'm looking up what carbs I can eat as I know we need good carbs to function, but really looking for a solid good suggestion of exactly what foods ( all ) are best to let this work. I had gained enough weight as to put me into the obese, have not had any regular exercise in 2 years & believe that caused this. Had very uncomfortable ball of the foot pain as a result of poor hammertoe / bunion surgery, which required a 3 hour corrective procedure 3 yrs. later. The change of balance caused 2 meniscus to tear & had removed.Very uncomfortable to use the treadmill etc. which I loved. Yes, this is an excuse along with lack of energy, & pain not to walk etc, & I'm sorry I let that happen. I believe the change from my normal good weight & stopping my exercise brought this on.
Looking for the best food plan to lose weight by the best foods to eat & I will start walking ASAP & use the eliptical machine so ease pain on the knees, & foot. I wear Orthodics, & have everything sold for the ball of the foot & nothing helps at all.
This site if FANTASTIC & most helpful in so many ways. Thank you.

Jenny said...

Robin, Orthopedic problems are very draining and do make it extremely hard to keep fit. As far as what to eat, we are each different so using your blood sugar meter to see what you personally can eat while hitting safe blood sugar targets works best.
This page explains:

How to Lower Your Blood Sugar

CHARLENE said...

Hi ROBIN ijust drink alot of water to keep my sugar levels down.

londa66 said...

Hi I'm on metformin er 500mg 24hr tab and I been on it for a year but when I went to the doctors to let her know my sugars are goi g high so they put me on 15 units of insulin at bed time still not helpi ng so now I'm on 30 units and I nedd help getting my a1c down it was 7.1 not good but I did quit smoking cigarettes. Today

Jenny said...


Your doctor may have to raise your insulin several more times until she finds the dose that works for you. Each person's dose is different.

Stopping smoking is very smart. Stick with it. I know it can be hard, but it is worth it!

CHARLENE said...


I told you i felt okay saturday and sunday ,bet monday it was worse .I went back to my doctor and he give me a new prescription named CIPLA -PIOGLITAZONE 30mg. I start today with it .

Jenny said...

CHARLENE Pioglitazone is the generic name of Actos. You might want to read up on it before you take it.

CHARLENE said...

ok iwill do so.

Where will i find it on the leaflet

Jenny said...

Charlene, The leaflet that comes with the drug is the patient version and doesn't tell you much.

I have summarized the problems researchers have identified with Actos, which is very similar to Avandia HERE.

CHARLENE said...


WOULD YOU PLEASE TELL ME MORE ABOUT Pioglitazane 30 and what is the does the don'ts to people.

Thank You

Jenny said...

Charlene, Everything I know about Pioglitazone (which IS Actos) is at

CHARLENE said...




Jenny said...


All I can give you is information--with its source--which is what I do here and on my main web site. It isn't my role to tell you what to do. You have to take some responsibility for learning and studying and discussing the issues that concern you with your doctor(s).

CHARLENE said...


Tired of being unhealthy! said...

So, when I was 14 or 15, my gynecologist put me on Metformin 500mg regular version three times a day, then slowly, the dose was increased to 850mg regular version twice a day, then she prescribed me 500mg twice a day regular version. I kept buying the prescriptions, got so tired that I never used them and threw way the entire supply toward the end of two years. Now, I am 22 and just started Metformin ER 500mg once a day. My new doctor now says she is going to increase the dose to 500mg ER twice a day over the course of next few weeks. I am going to discuss with her if I can go back to 850mg twice a day or 1000mg twice a day because I am tired and just want to be treated already!! And I don't have diabetes, but my insulin and testosterone levels are high.

Tired of being unhealthy! said...

Also wanted to ask if anyone has ever purchased Metformin from Healthwarehouse online pharmacy. It's licensed and has the VIPPS seal. I recently bought Metformin ER 500 mg from my pharmacy for $10 (30 tabs) at my local pharmacy. Found out about Walmart's affordable program, but then also found out about Healthwarehouse recently, and they're even cheaper than Walmart. Any suggestions?

Jenny said...

Metformin can make you tired. One thing you might try is a low dose of CoEnzyme Q10, which I have read is lowered when taking Metformin. I have found it seems to help with th energy. CVS's house brand has been lab tested and you can periodically buy it on buy-one-get-one-free deals.

I would not buy anything from mail order pharmacies because you have no idea what you're getting.

meghana said...

my dad is a type 2 diabetic for 4 years now. in the beginning he wasnt taking his medication regularly and so his HbA1c results (taken 6 months back) show 8.1%
i know that this implies that his diabetes is uncontrolled. he has been prescribed metformin hydrochloride by his doctor i.e. 500mg as Extended release form in the morning and metformin hydrochloride(sustained release form)-500 mg at night with the evening meal.
i am worried because he complains of muscle pain and sleepiness three hours after taking the medication ( he complains of this only after the evening dose and not the morning dose). is this a sign of lactic acidosis? should he discontinue the use of the drug? is he in danger? also my dad forgets the pill occasionally. he stays away from home so i cannot monitor his medication intake. how do i make him realise the importance of taking the medicine? he is careful with his diet though and does a little exercise and takes walks occasionally. is this beneficial at all?
also please enlighten me about metformin HCl whether there is a difference between the extended and sustained release forms. can he take the extended release pill in the evening too instead of the sustained release form?what are the signs of hypoglycemia and hyperglycemia that i should warn him about? please help. im really worried.

Jenny said...


These are questions you need to discuss with your father and his doctor. They are way beyond what can be covered in a blog comment. People with healthy kidneys don't have to worry about lactic acidosis, but only your doctor knows what condition your dad's are in. If you can't talk with his doctor you need to get your dad to contact them, with your help and ask.

As far as hypoglycemia goes, you can read an extremely good discussion of it in the book Dr. Bernstein's Diabetes Solution by Richard K. Bernstein.

meghana said...

Thank you so much.i would like to mention one thing though, my dad's renal function tests show healthy functioning of his kidneys. so that means he may not have to worry about lactic acidosis right? do u have any idea why he might be having muscle pain and sleepiness? what are theses signs due to?
i will certainly make my dad consult with his doctor, but i would like to get your advice too.
thanks again for your help. your blog is really helpful.

Unknown said...

Is he on a statin? They can cause muscle pain. High blood sugar can cause sleepiness.

Dana said...

My endocrinologist gave me a script for metformin er 500 because i have a problem with my sugar dropping all the time, she said i was insulin resistance not diabetic. I am still a little concerned about taking it when i already have low blood sugar. Anyone ever had this experience before?

Jenny said...


What you are experiencing sounds like reactive hypoglycemia. This happens when your blood sugar goes high, then your body pumps out insulin to lower it and doesn't stop after it starts to drop.

Your doctor's point in prescribing metformin is that it should stop the high from occurring, and without the high, you shouldn't experience the following low.

Metformin shouldn't cause hypos on its own, so there's no reason not to try it.

Another approach to try, if you haven't already, is to cut back on the starch and sugar you eat in your meals. This will also stop the highs and should prevent the reactive lows, too. Taking metformin along with a diet with less carbohydrate works very well to moderate insulin resistance, so you can use both strategies together.

monster said...

I am on Metformin ER 500mg for PCOS and it is a little strong and it makes me dizzy. Can you break them in half or will it give the full 24 hr dose at once? Thank you for any advice that you can give me.

Jenny said...

Monster, You can't split the ER pills. What makes them ER is the way the pill is constructed.

Amber said...

Jenny.. I am new to this site. I have PCOS and I have been dealing with it for 5 years now. I went to the doctor and he prescribed me Metformin 500mg. I took half the pill in the morning and the other half at night. On day 3 of taking Metformin I started to feel cold in my arms and legs, which felt very weird. I read about the side effects and noticed that was one of the side effects of lactic asidosis. I've heard this is a very rare thing. I am pretty healthy for the most part just overweight. I went back to the doctor and he got a little annoyed and said just quit taking it. He said he has never heard of this happening. I know I can't be the only person in the whole world with this symptom. Would it be better to ask him for the ER kind instead? I feel like this medicine will be the answer to my problems of PCOS. Please help!!

Jenny said...


Lactic acidosis is extremely rare with metformin--at the same rate as happens in people not taking the drug and usually associated with serious kidney problems.

Doctors who get annoyed when they don't know the explanation for something are very hard to deal with. I'd suggest going over to the discussion board on the discussion board and asking if any of the ladies there have experienced the same thing or heard of it. It is possible it is hormone related. I know I get attacks of the chills when my estrogen level drops too low.

Mike B said...

Does anybody know the patent status of Metformin ER? I just got my full 90 day prescription for 180 1000 mg pills filled. I have terrific insurance so it cost me nothing but Walgreen's informs me that my insurance saved me $1245.00. I find that astounding for a generic.

Jenny said...

Sounds to me like Walgreens is giving you the cost of the brand name version. The generics are available for $5-10 for a 30 day supply depending on how large the dose at most pharmacies.

Jenny said...

Sounds to me like Walgreens is giving you the cost of the brand name version. The generics are available for $5-10 for a 30 day supply depending on how large the dose at most pharmacies.

kllaux said...

My husband had been taking Metformin ER(4x500mg) in the evening for a couple of years now. Then some months ago, his prescription was changed by the pharmacy (with doctors approval they said) to 2x1000 tablets.

I know he should be more observant, but evidently they switched him to regular from ER at that time too and he never noticed. I just noticed it this morning when I picked up his meds.

Doctor is on vacation til next week, but shouldn't regular metformin be taken twice or more a day not all at once at night?

He has really had a problem keeping his morning sugars down the last few months.

Jenny said...

Regular metformin should be taken several times a day. Taking it at night probably doesn't cover his meals as well as taking the ER does. When meals go high then fasting blood sugar goes high too.

C Jane said...

Thank you for all your information.
I have been recently found out that i have PCOS. I am not over weight at all. I have been taking Metformin 500mg for 3 weeks now but only at night because i end up feeling terrible if i take it during the day. So far taking it at night works for me. I would like to know how long should i be taking metformin for because i would like to fall pregnant soon & i believe metformin will increases my chances, also will it be effective if taken at night only. Thanks Jane

Jenny said...


That's a question you should ask the doctor who prescribed the metformin. As I understand it, people with PCOS vary greatly in the extent to which they are insulin resistant, so my guess is that the effective dose would be an individual thing.

That said, 500 mg a day is a very small dose. Usually doctors start out with a small dose and increase it as people adapt. But my experience is entirely with people taking it for blood sugar control, where it takes at least 1000 mg a day (in people of normal weight) up to 4000 mg a day to see a full response.

seg said...

I have been Type 2 Dibetic since 2/2008 and test 3X's a day and never miss a test. I take 4 Glipizide XL 5mg in the morning
and 5 Metformin HCL ER 500mg ER before my dinner. My doctor always gives me rave reviews for my A1C. I think now he is only haveing me go to the lab once a year since I have it under good control. I have only had a reading of 200 just a few time and I can get it down to approx 110 in about 3 hours. Tonight I had a reading before dinner of 207 (YIKES) @7:04pm, so I tested again 4 hrs later to make sure it had gone down.
It was 210 @ 12:02am (5 hrs later?) so I took another 5 Metformin HCL ER 500mg ER. I have never had my Blood Sugar stay up like that before. I had a small lite dinner I was so concerned and that is why I took more and I will stay up and drink more water and take it again in about 2 hrs. I not only test 3X's a day I also document it everytime (religiously). Since it's so late I decided to go to the internet to see if I caused myself extreme harm taking the Metformin HCL 500mg ER again.
Thank You, Sally

Jenny said...

Sally, The worst that will happen after taking that extra metformin is that you will feel unwell for a few hours, but when I researched this I found no reports of permanent harm even for people taking far larger overdoses. My doctor prescribed an overdose for me by mistake some years ago which is why I researched it.

That said, if your blood sugar shoots up suddenly extra metformin isn't likely to help.

Sometimes unusually high readings come right before we come down with some infection like flu.

Did you wash your hands after testing to ensure that you didn't have something sugary on them that might raise the reading?

Did you add any new drugs or supplements?

If your blood sugar stays high for a week it would be worth a visit to the doctor to see what is going on. But one or two high readings could be anything including bad strips.

seg said...

Thank you for the quick response. I seem to be one of the lucky ones that I don't get sick or have a reaction on any medication.
I did test again at @2:16 and it was 138 and then I tested again at 7:17 and it was 136. I now have it down to 75 at 4:58 tonight just before taking my meds and haveing dinner. I think I'm back. Thanks again for all your help and great advise. I was just real lucky to find your blog last night.

Ressy said...

I hear about how wonderful metformin iis but not sure if it is for me. I took one 500 mg pill one day. A few hours later I had to lay down. I was so tired and yet my mind was awake. My respirations were very deep. I almost felt like I was not going to wake up. I prayed in my wide awake mind that someone would find me. After a couple of hours I came out of it but had the same thing happen 6 hours later.
Is this lactic acidosis?
I could benefit from this drug but am afraid. Is my fear justified?

Jenny said...


This is something you need to talk to your doctor about. It's a very unusual reaction and you should not take the drug again until you do.

Dr. Starks Banister said...

No note that Blood sugar of 168 is dangerously high is not true. My grandmother always test at 190-225 for the past 35 years and has had no strokes, vision loss, heartaches or other problems. She is 85 and doing well! I also know people that even with Metformin and Insulin still run blood sugars in the 200's and 300's for the past 20 years who have had no problems at all. To say it's dangerous is a bit inflammatory and the reason why most choose to take these drugs rather than diet/exercise to solve the problem.

GP said...

Good one dr had me seeing red for a bit, and then I realised it was just a fishing expedition. My grandmother has been player russian roulette for 50 years and is still going.

OuiBaby said...

After be scripted Metformin ER 500 mg,I stopped taking it because of the diarrhea. I was supposed to take it twice a daily but did receive any instructions as to when to take, only told to take it with food. I recently started taking it again but only once a day. Had my first reading below a 100 this evening before dinner. Will it hurt to take only once a day even though I was told twice a day?

Jenny said...


It won't hurt. Doctors are supposed to start you with the very lowest dose and only raise it after you've adapted. After you've taken this dose for a week without problems try adding one more pill.

Dr. Joe said...

I am a new diabetic and find your comments very helpful and informative. Thanks to all of you.
Dr. Joe

Tori Nelson said...

I am prescribed 500 mg metformin hcl er but I am terrified to try it , I am petrified of medicine but my sugar runs 250 and I know I need it ANY SUGGESTION????

Jenny said...

Tori, You can read up on metformin so that you'll know the real advantages and issues HERE.

500 mg of metformin is a tiny dose that won't make much of an impact, but it is a good idea to start slow. Most people need 1500 mg a day or more to see an effect, and metformin alone won't get your blood sugar down to a safe level.

However, metformin combined with cutting back on carbohydrates works very well. Try the technique described HERE.

Kitty said...

I've been on Metformin for 15 yrs. I take 1000 mg. 2x's a day. I live with occasionally diahrrea and stomach cramps most days. I'm also on Victoza, which helps with weight loss. My fasting is around 150 in the morning and goes up to 250 to 300 depending what I just ate. I just discovered Metformin ER. Should I switch? Would I be able to stay with the same doesage as I'm on now, if I were to switch? I should go on another medicine also, to lower my numbers. Any advice? I see my endo.dr. next mo. Thank - you.

Jenny said...

Kitty, Those numbers of yours are high enough to do a lot of damage, and changing the form of metformin you are taking isn't likely to help. You have tried stimulating your beta cells (Victoza) and reducing your liver's dumping of glucose.

So what's left--and most likely to work better--is insulin.

The other thing to try, of course, is cutting back on the carbohydrates you eat. If you haven't tried that yet, follow the advice you'll find at Some people find this makes a dramatic difference in their blood sugar, especially with metformin.

But if your beta cells no longer make insulin the only approach that will really work will be to use insulin, ideally both for the fasting state (Lantus or Levemir) or fast acting insulin for meals (Novolog or Apidra). Using insulin properly so that you get good control takes some self-education.

I'd suggest you start out by reading the main blood sugar 101 web site at using "Read This Page First" as a guide.

Susan said...

I take Metformin for PCOS. I was supposed to be taking 500mg three times a day, but I was really only taking it once a day most of the time because I was forgetting to take the others. So my doctor switched me to one 500mg of the extended release.

I'm confused, isn't that the same amount as just one of the immediate release pills? It seems like I should be taking a much higher dose of the ER. I'm a big person too, tall and overweight.

Jenny said...


Yes, the dose of the ER version is very close to that of the regular-maybe even a bit weaker. Ask your doctor if he meant to cut your dose by one third.

Susan said...

Thank you. I'll give them a call.

Olivia Paige said...

Hi the information is great but our walmart the metformin er 750 is not $4,00 wish it was

Jenny said...

Metformin ER is generic so you might try calling one of the other pharmacy chains and ask the pharmacist if they have a program where you can sign up for to get cheap generic drugs. I believe Walgreens might have one.

drjbo said...

I switched to taking Glumetza (branded version) from the generic version because the endo thought it was worth a shot. Fortunately, the Glumetza side effect were much less severe than the generic ER, and I found that eating yogurt at bedtime (I take 2000mg at dinner) help me tolerate the GI side effects. I am lucky enough to be able to get a 3 month supply for $10, but when I was out of town for a day, I realized I had left my meds at home. CVS wouldn't let me refill my Rx but was willing to sell me TWO pills for $22. I decided to skip a day. ;-)

Chyna Ruby said...

HEy Jenny;)

I've been taking metformin Er for the pass weeks without any side effects. The other day I ate frm a fast food restaurant and was immediately. Nauseated. I called my doc and was told that while taking metformin Er u shouldnt eat frm any fast food restàurants bc it will make u sick!

Jenny said...

While there are dozens of very good reasons to avoid eating fast food restaurants (trans fat, MSG, phosphates, ammoniated meats, high fructose corn syrup, etc) I have never heard anything that would link eating fast food with causing nausea when a person is taking metformin if they are fine when eating elsewhere.

It's possible you were fed some spoiled food at the restaurant.

Emily Knapp said...

I was put on metformin today for my pcos which is causing me to insulin resitant I have gained 50 lbs in one year and im taking 500mg ER once a day but after reading this im going to up my dosage next week to 1,000mg ER to see results. How do I get to see the best results fastest. Eating right and excersizing while taking metformin? What is the maximum number of carbs I should intake in a day?

Jenny said...


People with PCOS often find metformin helpful in reducing insulin resistance, though not always. It is certainly worth a try.

Many also find it helpful to cut their carbs way down. The less carbs you eat, the less insulin your body will secrete. However, if you are highly insulin resistant, you may still secrete a lot of insulin, even without eating a whole lot of carbohydrate.

Eating more protein than you need will also result in the secretion of insulin.

So there is no easy answer to your question. Everyone's body is different, and the degree to which people are insulin resistant also varies hugely.

If your blood sugar is not normal, you might benefit from using the technique found HERE to find out exactly how much carb you can handle in a single meal. However, many people with PCOS have normal blood sugars.

If your blood sugars are normal, I would suggest cutting your carbs down to a level you can live with for the next ten years or more, rather than a crash diet like Atkins that you can stick to for a month or two and then abandon (which is what most people do.)

Try cutting your carbs down to about 100 g a day for a start, and make most of the carbs you eat be carbs from fresh vegetables. Avoid processed foods full of chemicals and hidden MSG (which makes people gain weight) and do not eat at fast food restaurants where the food is full of msg and more chemicals.

Eat real meat without additives, eat cheeses that do not include phosphates in the ingredients (a sure sign they are processed cheeses) and stay away from sugar for the first few months to break your bad food habits.

A paleo diet works well for some people (you can read about it in various books), mostly because it eliminates so much of the processed, sugar and chemical laden food that stimulates hunger.

Just remember that what you are looking for is NOT a quick fix. You need to adapt your diet to something you can eat for a very long term without too much struggle.

And if your PCOS came on suddenly, I hope you make sure that the cause of the sudden rise in insulin resistance isn't a problem with your thyroid or rising blood sugar. If you haven't seen an endocrinologist it would probably be a good idea to check checked out by one. It seems to me that PCOS is being diagnosed by a lot of general practitioners who don't necessarily understand insulin resistance, but have recently learned about that diagnosis. It is vague enough that it can cover a lot of other conditions. Make sure that you have ruled out the other things that can cause a sudden rise in insulin resistance and weight.

Mike Guy said...

will metformin work for type one diabetes or is it for type two only?

Jenny said...

Research has found that metformin can increase insulin sensitivity in people with Type 1, allowing them to lower their doses. This is mostly a factor with older people with Type 1 as insulin resistance often increases with age. And of course, there are people with inborn insulin resistance who also get autoimmune diabetes.

However, it isn't usually prescribed, though there is some research to see if it might be helpful, given its apparent effect in countering both heart attack and cancer.

Rosa Behn said...

I have been taking Metformin 1000mg one tablet twice daily, my new doctor put me on Meformin ER 500mg two tablets twice a day what is the difference in the two doses? my sugar is in the hight 300 to low 400

Jenny said...

Rosa, The only difference between the two different versions of Metformin is that the new prescription should be easier on your stomach.

But metformin can't lower blood sugars as high as what you report. Try the technique described here: How To Lower Your Blood Sugar.

If that doesn't work, tell your doctor you want a more aggressive treatment, because those levels are high enough to cause complications. Lowering your blood sugar will prevent them.

Taunya Ewell said...

I also had problems with Metformin causing heartburn. I had an EKG done and it results showed a mild heart attack. My doctor assured me it was heart burn, but she put me on Metformin ER. My blood sugar is stable and there's no heart burn.

ram said...

Hi! Thanks for ur easy to understand description of metformin drug.
I was advised to take two tablets of metformin 850 mg tablets after BF and after dinner. My BG readings are within normal range except in the morning before BF- ranging between 100- 130. Bed time reading average is around 120 after dinner. Obviously, the drug is not that effective to control fasting glucose. I feel that taking one 850 mg SR after dinner in addition to 850 mg plain after BF , may lower fasting glucose. I seek ur valuable comment on this.

Jenny said...

You can safely change the timing of metformin pills as long as you don't exceed the total dosage for the 24 hour period that you were prescribed. So taking the pill before bed is fine.

If metformin does not make a significant difference to your fasting blood sugar, it suggests that your problem is not insulin resistance, but insulin deficiency. Your blood sugar is too good to address that with a basal insulin (like Lantus), but if it gets worse, that is a possibility.

Metformin works best when combined with a diet that reduces starches and sugars replacing them with fat and protein. Have you tried cutting back on starches and sugars?

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