June 24, 2010

Timing Your Metformin Dose

The biggest problem many people have with Metformin is that it causes such misery when it hits their stomachs that they can't keep taking it even though they know it is the safest and most effective of all the oral diabetes drugs.

In many cases all that is needed is some patience. After a rocky first few days many people's bodies calm down and metformin becomes quite tolerable.

If you are taking the regular form of Metformin with meals and still having serious stomach issues after a week of taking metformin, ask your doctor to prescribe the extended release form--metformin ER or Glucophage XR. The extended release form is much gentler in its action.

If that still doesn't solve your problem, there is one last strategy that quite a few of us have found helpful. It is to take your metformin later in the day, after you have eaten a meal or two. My experience with metformin--and this has been confirmed by other people--is that it can irritate an empty stomach, but if you take it when the stomach contains food it will behave.

There are some drugs where it matters greatly what time of day you take the drug. Metformin in its extended release form is not one of them. As the name suggests, the ER version of the pill slowly releases the drug into your body over a period that, from my observations, appears to last 8 to 12 hours. Though it is supposed to release over a full 24 hours, this does not appear to be the case, at least not with the generic forms my insurer will pay for.

Because there seems to be a span of hours when these extended release forms of metformin release the most drug into your blood stream, when you take your dose may affect how much impact the drug has on your blood sugars after meals or when you wake up.

For example, the version I take, made by Teva, releases most strongly in a period that starts 2 hours after I take it and continues strong over the next 8 hours. If I take my full 1500 mg dose first thing in the morning, my blood sugars at lunch will show the impact of the drug most strongly. Dinner will be slightly less affected--i.e. if I ate the same lunch and dinner I'd see slightly better numbers at lunch and I see the least impact on my next mornings fasting blood sugars.

If I take the same full dose at 2 PM I will see the strongest effect on my blood sugar after dinner, but I will see a lower fasting blood sugar the next morning than I would if I took the drug first thing in the morning. The trade off is that my breakfast blood sugar will be higher on that schedule if I eat any carbs.

Metformin also builds up a cumulative effect on your fasting blood sugar after you take it for a week. This effect is not dependent on when you take it. If you miss a dose you will probably see a small but immediate difference in your post meal blood sugars. But if your stop taking it for a week you will not only see that effect the day after you you stop it, you will also see a second notable increase in your fasting blood sugar and pre-meal blood sugar about a week later.

If you are taking metformin primarily to lower high morning fasting blood sugars, it may make sense to take your full dose right before bed--but the trade off will be that this timing of your dose may give you the weakest coverage before lunch and dinner, which may leave you with higher sugars for many hours of the day which counteract any advantage you might get from having lowered your morning reading.

Some people take half their metformin in the morning and half at night. That might give a more even effect throughout the day but because you smoothe out any peak in the drug's effect, you might see slightly higher meal time sugars than you would if you took it all at once.

Personally, I have learned after a lot of experimentation that taking all my metformin ER in a single dose at 2 PM gives me the most benefits. First of all it keeps me from having stomach discomfort, secondly it gives me a little boost with my dinner numbers, and finally it knocks a little bit off my morning reading.

Your results might be different, but you won't know what works for you unless you test different schedules.

If you want to change the time when you take your metformin there is one rule you must follow: Don't ever take MORE than your full prescribed dose during a 24 hour period.

If you take all of your metformin at 6 AM don't take any more until 6 AM the next day. If you have been splitting your dose and taking half at 6AM and half at 6 PM don't take a full dose of metformin until 6 PM the day after your last 6 PM dose.

You do not want to overlap your doses because you do not want to give yourself an overdose. Overdoses of metformin are very rarely life threatening--there is a case on record of someone surviving an overdose of 63,000 mg--but from personal experience I can tell you they are unpleasant and can make you feel very sick indeed. My old family doctor prescribed me an overdose years ago after he confused the top dose for the regular with the ER form--the regular can be taken in larger doses. It made me very ill though I was fine the next day.

Also, if you are testing a new dosing schedule, give it at least a week before you decide if it is working for you. That will let the long term blood levels stabilize.

Another helpful thing to know about metformin is that unlike many medications, it is not one that will cause rebound problems if you stop it abruptly. If you stop metformin all that will happen is that your blood sugar response will gradually go back to whatever it was before you started taking it. And you can start it back up at any time after that without any problems save the usual side effects people experience the first few days on the drug.

If you are not seeing the expected results from metformin, you may be taking one of the weaker generic forms. My experience and that reported by Dr. Richard K. Bernstein is that various generic brands of metformin vary greatly in their impact.

Many pharmacies will let you try a different generic brand if you want to try it. Dr. Bernstein recommends Glucophage, which was the original patented form of metformin prescribed before the generics came on the market. I haven't tried it so I can't say how useful it is. But if you have a choice, you might ask for it.

One last issue I haven never seen reported before is this. If you have trouble sleeping at night because you frequently have to get up to pee, it might be better to take your metformin before 3 PM because metformin may increase your need to pee at night. This is probably because the kidneys help remove it from the body and work harder in the 8 hours after you take the dose.



Anonymous said...

This is my favorite blog/website!
I recently started Metformin, I was on the verge of diabetes, I was told that many are hypoglycemic years before being diagnosed with diabetes. I also have hyperinsulinemia, (I have PCOS). I'm taking Glumetza ER, and at first it really stopped my crazy hunger, thirst and blurry vision but now my hunger is back and the odd time the blurry vision and thirst as well, but I notice I'm getting up in the middle of the night hungry and I have to pee! My sugars are never over 5.0 mmol/L and my lowest has been 3.3 mmol/L. I also started getting burning feet, I was starving yesterday and it happened, I thought that was only associated with high sugars? I'm controlling my diet so well, I'm exercising alot more, and I'm taking Metformin, so why am I still dealing with hunger and hypoglycemia? I take 2000mg of Glumetza ER, 2 pills in the morning and 2 pills around 7pm or 8pm at night, maybe I should change the timing? I can't up the dosage anymore, it's already at the upper limit. Also wanted to mention I recently started taking probiotics and oregano oil (it cleared up all the rashes I started getting, except the yeast infection still hasn't gone completely away). Could some of the issues I'm having be related to the candida dying off ? Thanks !!

Jenny said...

The "candida die off" is a fad diagnosis that I do not give much credit to.

It sounds to me like you are taking too much metformin. Your blood sugars are too low and you may also be blocking Vitamin B-12 absorption which would explain the nerve symptoms. This is a known problem with metformin and if your doctor did not test your B-12 level as soon as you reported nerve pain you need to find a new doctor, immediately.

If I were you, I'd back off that dose. You want your blood sugars are in the range between 4.7 (85 mg/dl) and 6.7 (120 mg/dl) at all times and you definitely need to get that B-12 level checked. B-12 deficiency causes nerve damage that can become irreversible. If that is what you have you'll need a shot of B-12 to fix it and prevent damage.

PinePienaarInfo said...

Jenny as always I have found value in all your words. There is so many things that you describe that I can personally relate to, thank you for the detail analysis that you provide regarding timing.
Just added a post to my blog about this article.

Anonymous said...

Actually it's called the Herxheimer reaction...when there is a healing crisis during treatment for candida. I heard you can get worse before you get better so I could be experiencing that as well. I also feel better when my sugars are anywhere between 3.8 and 4.5 mmol/L. anything higher and I don't feel so great. I am taking a B-complex which includes B-12, there is about 1000 mcg in it I believe. Maybe there is a problem with my kidneys or liver, I'll have to get that checked out. Also, have you heard about taking Metformin as a cream instead of pill form ? I recently heard about it but you need to go to a compounding pharmacy to get it done. I think if there is an issue with my liver or kidneys I may ask my doctor if I can try this, not sure what she'll say because mostly all the doctors I deal with are so hesitant to try different things.

Jenny said...

The question is "Who calls it the herxheimer reaction" followed by what are they selling which is usually questionable cures for vague sympoms. It's a fad diagnosis.

There is no such thing as metformin cream either.

If metformin is blocking absorption of B-12 in the gut it won't matter how much you take in pill form.

Normal blood sugar is around 4.5 (83 mg/dl) anything lower than 3.9 is a hypo and anything much lower than that is NOT good for your health no matter what you feel like.

There's probably nothing wrong with your liver. You are taking a very high dose of metformin and it sounds like it's more than you need.

Jenny said...

The only insulins that should be shaken are the cloudy ones with suspended particles. Right now that is only NPH. The others were discontinued They should not be shaken vigorously but gently back and forth. Dr. Bernstein explains this.

There is no reason to shake the clear insulins.

Anonymous said...

You're entitled to your own opinion concerning the Herxheimer reaction, but it isn't a fad diagnosis, research it yourself.
Also, as far as the vitamin B-12, does that mean that I have to stop Metformin ? Or would I have to take it in liquid form, or B-12 shots ? I don't think I would do well without Metformin at this point, it's really been helping me so far.
I think you're right, my dose may be too high, I am exercising alot more and keeping my carbs quite low, so that could be why I'm frequently hypoglycemic.
The topical metformin is something fairly new apparently as I heard about it myself not too long ago, just wondered if anyone else had as well. Here is a link about it: http://www.ovarian-cysts-pcos.com/news83.html#sec2

Jenny said...

Diane, Why are you asking me these questions when they are questions you should be asking your doctor? If you can't ask the doctor, find one you can. My job here is to give people ideas to think about and questions to ask. It isn't to tell you what to do in your specific case. The doctor is the person who can answer your specific questions about medication and treatment.

Jenny said...

Reviewing the link you provided re topical metformin, I want to make it clear for my readers that such a preparation would be helpful ONLY as a placebo. The dose is too tiny to have any effect even if taken internally and rubbed on the skin the amount absorbed would be negligible.

Placebos help a lot of people--that's why drugs are tested against placebo in controlled trials. Unfortunately, because chemically inert placebos ARE so useful, the people who profit from selling bogus cures will always have enthusiastic supporters who benefited from placebo effects.

People with diabetes however can't rely on placebo as blood sugar is NOT lowered to any significant extent by placebos.

RachaelHD said...

Jenny, you are a treasure! I was told to take my Metformin in the evening. End of story... I often end up taking it at bedtime because I forget. I have also been taking it on and off, it doesn't seem to change my bs numbers much, but I have noticed that I have a lot more energy especially in the mornings. With that energy I am able to walk or work out and *that* changes my blood sugar numbers a lot. Thanks for the info, I am going to experiment with my timing to see if I get any improvement.

Helen said...

Hi Jenny. I know you are familiar with my story. I have been taking Metformin for about four weeks at 500mg 2x/day. It seems to be helping with the liver dumping at meals - I don't go up over 160 the way I was before, but still go up over 150 briefly sometimes. This can happen with only 10 carbs. I'm on a low-carb diet - I've stopped counting, but I'm pretty sure it's between 40g and 60g carbs a day. I keep it low, because the 150+ sugars ensue at 10g or more at a meal.

My sugars aren't getting that low with the metformin. The morning sugars are still between 117 and 135, sometimes over 140. Seems to be higher when I'm hungrier. Lately I've been waking up in the middle of the night with my heart pounding and very hungry. This is a lifelong problem I've had off and on, but it's worse lately, I think because I'm generally eating less (I find it hard to eat enough on low-carb), though I do eat a protein snack at night.

I do have some nerve pain, but I had this before starting the metformin. How long would B12-deficiency nerve pain take to show up? I'm a little concerned about this. Should B12 be routinely tested in people taking metformin? I'd like to keep taking the metformin, since it has so many other benefits for people with diabetes. I also just have this sense that with it my body is struggling a bit less.

I very much suspect that the only modest improvements from the metformin, low-carb, and increased exercise (which seems to have the greatest short-term effects), are because I'm MODY 2, but it will take a while to find that out for sure. I recently had a cholesterol panel done. It was outstanding, even better than in the past. Triglycerides were 44. One of the benefits of being MODY 2, if I am.

As usual, I have several thoughts that don't fit in this topic. For instance, if you ever care to cover it (don't feel you need to here), I'd be interested in your take on caffeine and diabetes. I also don't understand why small doses of insulin aren't used in MODY 2 patients. It worked when I was pregnant. I did only need a little. Again, I don't expect you to answer this here, but if you are interested in covering those topics in a blog post, I'd be eager to hear your point of view.

Jenny said...


You are right, these are more questions than I can begin to answer here.

Metformin would not be of much use for MODY-2 unless the person also had some IR, possibly age-related or a problem with liver dumping which Metformin can block. But the flaw in MODY-2 involves the "thermostat" for normal sugar and that isn't something metformin affects.

People taking metformin should have periodic Vitamin B-12 levels taken. Usually it takes many years for the deficiency to occur, if it does, but if a person was already marginal for B-12 it might become an issue.

Helen said...

Thanks, Jenny. I do think that I had recently developed some insulin resistance leading to/resulting from a 20-pound weight gain. This may have helped pushed my numbers to the "clinical" category. I do seem to dump glucose with meals, and the metformin seems to help with that.

Harold said...

I take Metformin 500mg 2x/day, once with breakfast and once with supper. I have been testing for two weeks now and have noticed a big drop between my first and second hour readings. For example last night I wanted to see what would happen if I eat pizza the way I used to. My first hour # was 147. My second hour # was 107. I think I'm going to try moving my evening dose to one hour before I eat to see what that does to my first hour #.

Unknown said...

@Harold Better check 3rd, 4th and 5th hours to be sure. Pizza can be tricky. The fat slows down the massive amount of carb so it can hit your bloodstream much later than other foods.

PRIVATE said...

What's the difference between Glumetza, Glucophage XR and Metformin ER ? I read that Glumetza is not equivalent to Glucophage, this worries me.

Jenny said...

Glumetza, Glucophage and Metformin ER all contain the same active chemical, which is metformin. Glucophage is the brand name for metformin. Metformin ER comes in a matrix that releases the drug very slowly. It is a generic drug and different companies use different components in the slow release matrix but the metformin in the same.

Glumetza uses a different kind of slow release matrix that supposedly releases it in the stomach not the intestines as happens with some versions of the ER. But the metformin you get is the same stuff in all these drugs.

If you don't get digestive side effects the plain old cheap generic Metformin ER is all you need. Otherwise it might be worth trying the Glumetza as some people find it easier on their digestions.

Cutting down on carbohydrates or taking your metformin in the afternoon may also cut down on the digestive side effects.

PRIVATE said...

I'm currently on Glumetza but I've been seeing the pill in my stools, does that mean it's not getting absorbed properly ? Maybe I should ask my doctor to give me the Glucophage XR instead.

Jenny said...

All you see in the stool is the matrix, not the drug. This is normal.

Unknown said...

I am so happy you addressed Metfomin because even though it is the most widely used and "safest" historically, I haven't seen a lot of personal commentary on it. Tomorrow morning I am facing my 1st follow up A1C since diabetes 2 diagnosis - and I am curious to learn what changes have occured. My 1st A1C was an 8 - I still fight the carb craving in the evening but... life is a learning process. Thanks for your great blogging! I am a follower and enjoy yours posts. (: D) enise

Patty said...

I started metformin 500 2 x daily about 3 weeks ago. I have had higher blood sugar readings (over 100) since taking the metformin. I am on it because I have been keeping my blood sugar under control with diet and exercise but have been unable to lose any weight. The doctor thought we would give this a try. I have an
A1C of 6.2 before metformin. I have had constipation since starting it and wondered if this is something that could happen being that it usually causes the other. I walk/run 3 miles a day and I have not been able to lose weight for over a year. I drink well over the 8 bottles of water they want you to drink. I watch what I eat using nuts to fulfill my snacks and apples and yogurt as part of my lunch. should I stop the metformin or is there another med I can try instead?

Jenny said...

Patty, Metformin is probably slowing your digestion enough that you are seeing the normal rise in blood sugar that follows eating starches and sugars, which you were missing earlier, because it came before you were testing and quickly resolved. But a reading over 100 is still completely normal and my guess is that it is resolving at the same speed as before.

Cutting back on your carbohydrate intake may alleviate some of the constipation. Apples are very high in carbohydrates as are many yogurts. Try keeping the carbohydrate content of each meal to 20 g or less and see what happens. A spoonful of metamucil (the kind without sugar!) may also help with the constipation.

There is no other drug that I know of that is helpful for weight loss and blood sugar control without dangerous side effects. But metformin works much better with a lowered carbohydrate intake.

If cutting back on carbs doesn't help you need to discuss this with your doctor.

Patty said...

Thank you - I will alter my lunch and lower my carb intake. I just wanted to let you know that I have been an IBS sufferer since I was 18 (now 50)I have always been able to control it by taking Senikot nightly but since starting the Metformin this no longer helps. I have read that maybe by adding magnesium to my diet may help with both constipation and blood sugar. I am grasping at straws trying to find the easiest most homeopathic fix. Let me know what you think.

Vanessa said...

PLEASE HELP!! I'm nearly 28 years old. I've started taking Metformin 850mg /once a day because I have PCOS and my sister-in-law has the same and recommend it to me. I also have a Hiatal Hernia, GASTROESOPHAGEAL REFLUX DISEASE, Fatty Liver (Hepatic steatosis grade II), Migraines, Vesicoureteral reflux grade II, treated with Helicobacter pylori in 2008 and also I was operated with an abdominal exploratory laparotomy last year for a mistaken Vesicovaginal fistula (VVF) which it wasn't there but now I suffer with Urgent Urinary Incontinence due to the operation. Since the operation in April 2009, I also suffer with chronic cystitis and I take a different course of antibiotics every 3 to 4 weeks but I'm resistant to most of them now. My last one is Amoxicillin 875mg/Clavulanic Acid 125mg which I've taken min. five more times previously and I started this course at the same time as Metformin 850mg and I now have thrush in the vagina and anal area, my questions are if anyone can help:
Can Metformin affect any my other health problems?
Can Metformin make thrush worse or start it?
When the diarrhoea symptoms will disappear? (I've been taking this for a week only)
Should I ask my GP first before continuing this medication?
I just would like more information from anyone familiar with this medication and please help me with my urine problem too. Thanks a million.

Jenny said...


You need to talk to your doctor about this. All those antibiotics will destroy the population of helpful bacteria you need in your gut, and adding metformin on top of it probably isn't a good idea.

Have you had a urine culture to see if there is an actual infection? If so, was the antibiotic matched the the cultured infective organism? If you urinary tract did not culture, you may have a subclinical infection which should be treated with one of the antibiotics that are known to get to the urethra (if that is where you are having symptoms.) Not all do.

I have dealt with this issue myself, and found few doctors understood it. Drugs that I have found helpful for subclinical infections include generics Metronidazole and Doxycyline.

It might be helpful to lower your blood sugar, because sugar in urine feeds these infections. Cutting way down on your carbohydrate intake, with or without metformin might help here. Have you tested your post-meal blood sugar to see if it is high? Did your doctor do a dip test for glucose in urine?

Eliminating gluten helps many people with reflux. It's worth a try too.

If you don't have an actual infection but your urinary tract is inflammed because of the surgery, you might try a few sessions of acupuncture with someone who is associated with a mainstream hospital (they are often the most competent.) Acupuncture can't help with an infection, but it can dramatically calm residual inflammation if you are left inflamed after something healed.

After you are done with the antibiotics, you should take a probiotic called Fem-dophilus which will repopulate the helpful bacteria in your reproductive tract and possibly urinary tract. It works very well--much better than yogurt as it contains the proper strains of helpful bacteria, which yogurt does not.

Wishing you the best.

Vicky-49 said...

Vicky-49 I am almost 50 and until recently say the last 4 months my fasting sugar was ok. Recently it has started running 140 to 175. and my a1c was 6.6. I am now suppose to take 1 500 mg Metformin every evening. I have been taking this now for 10 days if anything my numbers are getting higher.This morning it was 174 I normally take this with my thyroid med about 7 pm every night. do you think I should try to take it earlier in the day. I'm afraid the dr will up my dosage and I have been told that to much can damage your liver.

Jenny said...

Vicky, Metformin won't damage your liver, and you are taking a dose so low it wouldn't be expected to do anything. People have taken huge overdoses of metformin by mistake and survived. Metformin usually doesn't have an effect until you are taking between 1000 and 2250 mg a day.

ssbelle82 said...

Hi Vicky, I'm not sure if you will see this, but I just wanted to mention that you might not want to take your Metformin with your thyroid medication. I have discovered the hard way that it interferes with the absorption.


Unknown said...

i was diagnosed with diabees in 2010,and put on metformin hydrochloride tablets I.P.sustained release.i was having 500 mg for a year when on a strict diet.the sugar levels were normal.then now in 2012 my sugars hav gone up and show 300 fasting at times,when i increased 500 mg with dinner.when it is again out of control i have 1 tablet 500mg 3 times a day ;breakfast, lunch, dinner.is this an overdose?i want to bring it back to 500mg once a day during breakfast.what do u suggest i should do?

Jenny said...


That's far from an overdose of metformin, but if your fasting blood sugar is at 300 mg/dl you need more than metformin to avoid serious diabetic complications.

Try the strategy explained at http://bloodsugar101.com/how.php . If that doesn't work, you need to see a doctor to find out why your blood sugar has risen so high so quickly and to get appropriate treatment.

Krishnendu Saha said...

I have been reading your blog for a lot of knowledge on Diabetes & I find it very useful. Thus I write to you about my sugar problem.
I was recently diagnosed with Diabetes, ( fasting was 350). The doctor put me on metformin XR twice a day, within one month he took me of medicine as my fasting sugar had dropped to 111mg/dl & my PP mg/dl also 111. Both the figures are same; sometimes my fasting could be a shade higher than my PP. I don’t understand this as to how my Fasting is higher than my PP. I have read your article as how some people have high Blood Sugar in the morning, is this case for me.
Do I need to go back to medicine? Currently I have been able to control my sugar by exercise & diet

Jenny said...


Since you did so well while taking the metformin and are so close to diagnosis, it seems like it would be a good idea to keep taking the metformin. Otherwise, you may find that it gets harder to control your sugars. Metformin lowers your insulin resistance by changing how your liver and muscles burn glucose. It also helps lower fasting blood sugar, but unlike other diabetes drugs, it should not cause dangerous low blood sugars.

Did your doctor explain why he stopped the drug? If there wasn't a problem with it, it might help you long term to stay on it.

Krishnendu Saha said...

I have been having this reading range of 100-111, both for fasting & PP, for the past 3 & 1/2 months & I have been off medicine for the same duration (3 1/2). I regularly check my BS. My current HbA1C score is 6.1 & my 2hrs OGTT score is 145mg
I use to have a horrible life style; I changed all that in a day & then my readings started coming in the range of 80-85 for fasting, with the help of medicine. Then my doctor took me off medicine & told me that I probably had Diabetic shock, but he has put me under observation.
He keeps a tab over my BS levels. The last PP sugar was 111 & he was happy with the reading. Now he wants my Fasting score after a month, then he will decide what to do. But I know my Fasting comes at about the same range.
Do you think a score of 111 for PP is good & what about my Hb & OGTT scores ?

Jenny said...

Krishnendu, Your fasting readings are still in the prediabetic range, so if you can get down to truly normal with metformin, I would think that would be a plus. The post-prandial readings are great, but there is a pattern of diabetes onset most common in men where the fasting rises before the post-prandials do, so I wouldn't ignore that higher than normal post prandial reading. Especially since it is very common for people to gradually go back to their poor eating habits over time as the crisis abates.

If you don't take the metformin you should not rely on tests at the doctor's office a few times a year, but should get a meter and periodically test your blood sugar after meals to ensure it isn't creeping up again.

Dave said...

Thanks for the great service you provide everybody here. I have prediabetes as well as low HDL and high triglycerides. I am already taken statin and niacin at bed time and have been prescribed the regular metformin (not ER). I am concerned about the interaction of the metformin with the niacin. I don't normally eat much for breakfast, so my plan is to take the metformin at lunch and maybe it will be out of my system by the time I take the niacin at bed time. Do you have any thoughts on that plan and do you know what I should be looking for if there is a reaction between the metformin and the niacin?

Jenny said...

I am not aware of any interaction between metformin and niacin.

Metformin of any kind builds up to some extent in your system over time--it's supposed to and helps it work properly. It takes about a week to get it completely out of your system if you stop it.

Unknown said...

Hi Jenny, I just came across your website. I have been a denial diabetic. A1c's 8.7-9.2. I tried glypizide in the fast and lowered me so much i told my Dr. i couldn't take it. Now 4yrs later he wanted me on glybrizide, but i asked for Metformin (i've heard better for you). He has diagnosed me 500mg x 2days see him in 2 weeks. Can you tell me how to start? How i'll feel? I was very shaky and gittery the last time. I know i'm way over due and need to take something. My down fall is breads and sweets...So where do i begin??

Jenny said...

Dave, Because your blood sugar has been so high for a long time, anything that lowers your blood sugar may make you feel shaky, but this is a short term phenomenon that should fade out very quickly. You should get a blood sugar meter and test your blood sugar when you feel shaky. Unless you see blood sugars under 80 mg/dl your blood sugars are in the normal range, and you just have to wait it out. This is called "false hypo."

Metformin often causes stomach and intestinal reactions the first few days people take it, but those too should wear off.

Whatever drug you are taking, it will work better if you combine it with the strategy described at http://bloodsugar101.com/how.php . Give that a try for a few weeks and you may see a great improvement.

Chelle D said...

I'm on 2000 mg Met daily. (Gradually increased over many years). Been on 2000 for at least 8 years now.
I take 2x 500 mg tabs in am & 2 with dinner. (I've also been on Lantus for about 8 yrs.. gradual increase dosing of that also).

Doc recently (12 wks) added NovoRapid for meal insulin. My bedtime numbers are still high. I asked about moving one of my am 500 mg tabs to lunch or dinner... to help cover dinner blood sugars. Doc said that's not how it works, that its a build up.

So, essentially, is the 1000 mg morning & 1000 mg dinner going to keep my met dosage "even" throughout the day? Or do You think taking 1500 with dinner would be beneficial to try?

I also have periphial nerve damage in feet. So, this could be caused by B12? (or lack thereof). Taking B12 drops,or a sublingual B tablet might help my foot pains? Could it be beneficial for the deadended neuropathy feeling?

Jenny said...

Chelly, I have found some brands of metformin are "peakier" than others. You probably could try moving the doses around, as long as you make sure never to take more than 2000 mg in one 24 hour period. If it doesn't make a difference, go back to your old schedule.

Your doctor should be testing your B12 levels since you have been taking metformin for so long. If they aren't aware of this, make them aware and demand the test. If your B12 level is low you would need a shot. When metformin lowers B12 it is because it damages the cells in the lining of the digestive tract that are supposed to absorb it. So only by putting it into your blood stream will you get it.

Both high blood sugars and B12 deficiency can cause damage. But if B12 deficiency is causing yours you don't want to screw around because unlike the damage from high blood sugar B12 damage may not be reversible.

Anonymous said...

Jenny, thanks a ton for sharing your insights. I've been recently diagnosed with T2. Your site was a great blessing to help me understand the medications and their effects & side-effects. Such information is rarely given by the doctors where I live (India), who tend to have the attitude of "Trust Me. I'm a doctor".

Its especially great that your advice is based on scientific papers which many like me may not have access or be able to comprehend fully.

God bless you.

Jenny said...


Thanks for your very kind words!

pulp said...

I'm so glad to see your blog still active! I wish I'd found you sooner after my diabetes diagnosis.

I've had roux en Y surgery: aka RNY, aka gastric bypass. We must take sublingual or injected vitamin B12 forever. I only recently read that metformin interferes with B12 absorption.

Since my shortened small intestine no longer absorbs much or any B12 anyway, do you think it makes any difference how much B12 I need? I'm down to 500 mg of metformin daily since surgery (the surgeon said I could stop taking it, but I don't think I'm stable enough yet) and I take 1,200 mcgs of sublingual B12. (The surgeon also said I didn't need to take B12 daily, but I do not believe her.)

Should metformin and sublingual B12 be taken hours apart, or does it matter when they're taken?

Thanks so much for your information!

Jenny said...


Surgeons are really good at surgery, but not necessarily well educated about long-term health issues. Your family doctor should periodically send you to the lab for a test of your B-12 level and if it is low, you will need shots. This is true of anyone who has been taking metformin for several years, and with your surgery it is all the more important.

If your family doctor isn't aware of this, educate him. The problem with B-12 deficiency is that by the time you have symptoms, you will also have permanent, irreversible nerve damage which causes symptoms very similar to diabetic neuropathy but which can't be reversed by normalizing blood sugar.

So you need to act before the symptoms arise that would get a doctor who isn't aware of this issue to send you for a test.

Because 10% of patients won't get enough B-12 from sublingual tablets it is essential that you have this test every year or two

Here's a paper intended for doctors about the issues that need to be tracked after people have WLS.


Unknown said...

I was recently diagnosed with diabetes and prescibed 500mg of metformin 2x/day. I usually take it at breakfast and dinner. However, I forgot to take it today. Should I go ahead and take one dose now (3:30pm) or just wait until dinner? I tried to call the pharmacy but was on hold forever.

Jenny said...


It would be irresponsible for me to tell a stranger what dose of medication to take, and possibly illegal.

Unknown said...

I was curious if you heard about the University of Zurich report linking red and processed meat to early death?

Jenny said...


Yes. This is yet anothor associational studies where it's tough to know if the problem is the sausages or what is eaten with them. It is also possible that a diet filled with cheap processed meat is a marker for poverty and the inability to access decent medical care. That said, it is also possible that the chemicals in processed meats are unhealthy. There has long been question about nitrites and there are definitely problems with phosphates. Personally I consider the phosphate solutions injected into a lot of meat today more worrisome.

Unknown said...

Jenny - Thanks for your great work. I'm 70 years old and have been moving towards Type II diabetes for the past several years. My weight is normal and I walk briskly five miles every other day, schedule permitting The doc tells me I'm now officially a Type II. My triglycerides are 164; Glucose fasting is 149, and 200 two hours after dinner. I'm been prescribed Medformen HCL 500MG once daily in the evening, for seven days, then one pill at breakfast, then one pill at dinner, after the seventh day. My problem is I can't get past six days of one pill a day, due to severe stomach cramps. Some so strong I feel I should visit an Emergency Room. After about 18 hours, the cramps subside. QUESTION - Could the cramping be caused by taking Simvastatin tabs (40mg) and blood pressure tabs, Lisinopril/HCTZ? In the same 12 hour period? Thank you, in advance.

Jenny said...


I haven't heard of drug interactions being the culprit here, but you should call the registered pharmacist where you buy your drugs and ask them.

Beyond that, you could ask your doctor to switch you to the Metformin ER (extended release) instead of plain Metformin. Many people find it easier to tolerate.

If you still have trouble with that, you could also ask your pharmacy to dispense another generic brand. I found that the Sun Pharma brand made me sick, and I'd been taking other brands for years without problems. Walgreens will order a different generic for you if you ask them to. (Teva is the one I currently use.)

Some people find they can better tolerate a branded version called Glumetza, which you can ask your doctor about if the other solutions don't work.

Unknown said...

I been taking metformin and recentley I took it late and my sugars dropped down to 90 before bed and thought I was going to faint...Do you think its more my anxiety or was I really low blood sugars....

Jenny said...


What you experienced is called a "false hypo." It happens when your body is used to running high blood sugars and your sugars drop to normal. That's because our body judges how high or low blood sugar is by comparing it to what it usually is.

If you hang on and don't raise your blood sugar from that completely normal 90 mg/dl reading, over time your body will adapt and no longer act as if your blood sugar is dangerously low. The range that is truly dangerously low begins at less than 60 mg/dl and really becomes threatening in the 40 mg/dl range.

Most people with Type 2 will respond to true lows like that with a burst of stress hormone that will raise blood sugar. Unfortunately, with false hypos you sometimes get those bursts of hormone too, which is why you feel stressed. Just wait it out and it will adapt.

Dabondis said...

Hi Jenny! I'm loving your advice!i was told by obe doctor I'm Type 2 Diabetic. My A1C 6.2, 3h OGTT 149-impaired, Fasing blood sugar 78, 2h PP 108, & prescibed Januvia 50 mg/day. Went for second opinion told I have a Metabolic Imbalance & prescibed Metformin 500mg/day. Yes I'm having the diarrhea but I'm more curious as to if I need these drugs?? I have a family Hx of Diabetes & states its for preventive measures! I'm not sure if I need these meds?

Unknown said...

I have been reading your blog for knowledge on Diabetes & I find it very useful. Thus I write to you about my sugar problem.
I was recently diagnosed with Diabetes, ( fasting was 140 pp was 220). The doctor put me on metformin sR 500mg a day, after one week with medicine as my fasting sugar had 140mg/dl & my PP mg/dl also 220.
Do I need to correct dose of medicine?

Jenny said...


You need to report that result to your doctor. That is a very low dose, up to 2000 mg a day is common.

Jenny said...


Sorry to have missed seeing your question. Januvia is a dangerous drug. You can read the reasons why HERE.

Your A1c is quite high, though it isn't a terribly accurate test since oddities of your red blood cells can give a false reading. However your 2 hr GTT result was also high. When you test after meals test 1 hour and 3 hours after eating to see if perhaps you have a delayed spike.

Metformin is a good, safe drug with anti-cancer and anti-heart attack properties. There's nothing wrong with taking it. However, combining it with Januvia can make the stomach symptoms
worse. Usually over a few weeks people adapt to it.

You are lucky to have a doctor who takes prediabetes seriously since it very often will progress to diabetes, but not before killing off a lot of the insulin-producing cells you still have left now. However, doctors have been kept from learning of the problems with Januvia as the drug companies keep high profile doctors on their payroll who poohpooh every serious problem that comes up with their highly profitable patented drugs. In time, the public will learn about the problems with the whole family of incretin drugs, but not until a lot of damage has been done to those taking them.

Teresa said...

Hi Jenny,

I just started reading your blog and it is very interesting and helpful! I have a few similar problems as well. But I was wondering if you know if Glumetza causes a feeling of tightness in your chest and heart palpitations on and off? Can it cause a blood pressure problem? I also notice when my sugar starts rise when I eat I get a dizzy feeling in the middle of my forehead and feel kind of out of it. When I say high it only about 140-160 range. I know when its high and I know when its low it is a terrible up and down. When I lower my carbs it goes be low 80 and I I only feel good and normal when my sugar is between 110-135. Is it possible everyone is not the text book numbers and someone can have their own range? Thanks Teresa

Jenny said...

Metformin shouldn't be causing the symptoms you describe. It causes stomach pains and occasionally stomach pains that feel like chest pains, but not palpitations or high blood pressure. If anything it should lower blood pressure by lowering circulating insulin.

People who can feel their blood sugar fluctuating will feel good in whatever range they are most often spending time in. That feeling gives you no clue as to whether the blood sugar level is doing damage.

If your blood sugar is a bit too high and you lower it and you feel bad you are almost certainly experiencing "false hypo" which is discussed HERE.

It's pretty clear that the damage done by high blood sugars is linked to specific blood sugar levels. But the way you feel at various blood sugar levels tells you nothing about health. I have met people who were walking around with blood sugars in the 400s who felt fine. But over time blood sugars that high would damage all their organs.

Canela Q said...

Dear Jenny, I take generic Metformin for insulin resistance\PCOS. My question is about timing. I take my pill plus a Vitex supplement with my breakfast and coffee. I would like to add a probiotic capsule I purchased at Costco(Natures Bounty). Is there recommendations on when to take the probiotic to allow its full efficacy? Can I take it with my morning pills or should I wait for later in the day? I enjoyed your article and look forward to your experienced suggestions. -Canela

Jenny said...


I don't know enough about probiotics to know how one would interact with metformin. Perhaps you could ask your pharmacist about this.

Tturner said...

Hi Jenny, I am newly T2 diagnosed. I sees few doctors, read your books, website and blog and find them very useful. But I am still looking for answers to my question and hope you can help.

I am Asian and skinny (38kg). I loss 6kg -15% of my weight since I applied low carb diet of 40-50g of carb. a day. I don't want to loose weight as most diabetic cases, in fact i want to gain weight. I am in Glucophage XR 1000 at lunch time. I don't have problem with fasting BG (always under 100) but after meals can go to 120-140. Do you have any advice on what time I should take the medicine so I can good BS after lunch and dinner? Does Metformin make me loose more weight? I am looking forward to your knowledgable suggestions. I feel lucky to find your website as I found it most useful and make sense the most among others.

Jenny said...

Various brands of metformin extended release behave differently with some more likely to cause a peak concentration than others. Glucophage, if it is the brand version, is the most even, from what I've heard. So it might not matter when you take it.

A reading of 120-140 after meals while eating only 40-50 grams of carbs suggests that you might do better with a slightly higher carbohydrate intake and prandin (repaglinide) at meals, if you can get a doctor to recommend it. You are probably not making enough insulin, and while lowering carbs helps, it isn't helping enough. Insulin at meals might be helpful, but it is hard to get doctors to sign on.

he biggest problem with Prandin it is that it often causes weight gain, but that isn't a problem for you. However, you would have to eat more carbs with it as it can cause hypos.

For a doctor to prescribe anything, however, you would have to up your carbs for a while before your appointment and blood tests so that you get the much higher blood sugars you get without a very low carb diet and demonstrate to the doctor that you need help.

Doctors don't understand the strong impact of lowering carb intake on your blood sugars and will tell you your post meal numbers now are normal, which would be true if you were eating 300 g of carbs a day, but not at 50!.

If you can show numbers post meal in the 200s they will be happy to prescribe something to help.

I was in a similar situation to yours for some years, and finally found a doctor who when she saw that I could go over 200 mg/dl eating only 40 grams of carbs at once prescribed insulin for me. I felt so much better!

The situation is different for very heavy people who are largely insulin resistant, but someone your size with those readings after eating a low carb meal is almost certainly low on insulin.

Tturner said...

Hi Jenny, thank you! I like the trick you told me to doctors because when I show them my BS numbers , they even think i am just pre-diabetic and doing well since my latest A1c is 5.9 thanks to low carb.
If I am low in insulin, does it mean I almost run out of beta cells, and become type 1 in future? my fasting number is usually good under 100, after meal of 15g carb it can go to 120. If I take insulin, do you think I should continue Metformin? Thanks very much!

Jenny said...


Your numbers right now are very good, there is no need for insulin if you are only reaching 120 mg/dl with 15 g of carbs unless you can't sustain the way you are eating.

If you do end up using insulin at some future time, metformin will cut down on the dose you need to take, so it is good to take it in combination, but for now, you are doing fine.

Tturner said...

Thank you Jenny for your good advices as always!

DOC said...

Hello Jenny
I was originally diagnosed type 2 in 2009 with an A1C of 7.5% at that time. Shortly after that time I lost my health insurance and was trying to treat myself with workout and diet. I was, and still am taking Chromium to attempt to be able to process glucose better, and now since May of this year I am on Metformin twice a day. I had an A1C test last Friday and my A1C is now 7%

My Cholesterol total was 175mg/dl, triglycerides 91, HDL 45, VLDL 18 and LDL 112.

Just giving you some backround info, I am still new at interpreting all this data.

My issues at the moment primarily are
1) I am to the point of I don't know what to eat, everything seems to make me spike up!! I had a bowl of gluten free rice krispies with rasberries and mg BG went to 250, and I felt like crap!! My morning fasting BG is normally 110 to 120 BTW.

I have also found on many occasions after going out to dinner if I had a meal of steak, veggies and a beer that I could eat a desert and not have much impact, like a BG og 140 to 150 2 hours after eating.

I know for long term , which I am calling for an appointment with today, I need to see a Diabetic Nutritionist, but for the short term as in like right now, I don't know what the heck to eat anymore!! It just seems very unpredictable.

Second issue that you might have toughts on is Neuropathy. My feet are killing me. I want to do the treadmill as I need to lose weight anyway, but when walking is as painful as it is it is hard to stay motivated to do the treadmill. My Nurse Practitioner prescribed Neurontin which I only took a few days, it made me sleepy, which I already have issues with being that I have narcolepsy, and it did nothing for the pain anyway. I am taking a supplemet that is a combination of B1, B12 and R-Alpha Lipoic Acid that I recently purchased. I do not know how much it will help but figure it is worth a shot.

For now I am going to do weight lifting hoping that will help with lowering my numbers , but if you have any other thoughts on what else might help with my feet I would appreciate it.

Thanx, have a great day

Anonymous said...

What a great column you have!
I've been Type 2 for about six or seven years (on Metformin the whole time). Currently taking 1500 mg Metformin ER (2-750 mg tablets) at bedtime each night. Also taking Bydureon once weekly and Lantus nightly. My daytime Post Prandial readings are quite good (as long as I stay under about 12 or 15 carbs, which I do), but my morning readings have always been a problem. The recent addition of Lantus have brought those morning numbers down from 170 to 111. Of course, I want to hit less than 100. SO, the question is: do you think I could benefit from increasing the nighttime MetER to 2000? Frankly, I'd rather do it that way than by increasing the Lantus.
Finally, I know Bydureon is questionable (and its long-term dangers to thyroid are unclear) so I may ultimately ask the doc to DC the Bydureon and simply add Humalog.

Jenny said...


The carbohydrates you eat--starches and sugars--are what raise your blood sugar. Rice Crispies are very high in starch. If you measured how much you ate, you might find you had twice as much as the portion size listed on the label, too.

Read labels to figure out how much carbohydrate is in the foods you eat. Figure out how many grams are in the meals that don't raise your blood sugar, and try to eat that amount of carbohydrate whenever possible.

The best way to reverse the pain in your feet is to keep your blood sugar under 140 mg/dl at all times. This is not easy, but people do it, and when they do, over a few months their nerves heal up. Doctors will sometimes give you pills, but the pills only turn off the pain signal, they don't stop the nerve death that is causing it. You want your nerves to heal!

If you haven't tried the technique described here, it's a good place to start: How to Lower Your Blood Sugar

Jenny said...


If you are keeping your meals controlled, 111 isn't all that bad. The problem with boosting Lantus is that it can cause you to go low at night which will, paradoxically give you higher readings when you wake up, as your body secretes stress hormones to raise blood sugar when it is too low. Sometimes you will get better readings by lowering your Lantus dose rather than raising it.

You can always try more Metformin, though it may be tougher to tolerate.

Tturner said...

Hi Jenny, i am taking Glucophage XR 500mg twice a day, in the morning and evening. My fasting BG goes usually low 70-80. Is it ok to take one Glucophage XR in the morning and one fast acting (not extended) after diner then i can avoid the low fasting BS or any suggestion from you? Thank you!

Jenny said...


Those morning readings aren't really lows. The normal range extends down to 70. If you aren't taking insulin or insulin stimulating drugs those are fine fasting values. They may feel like lows because you aren't used to them, but if you can be patient, your body will adapt and you will feel good at those normal readings.

As far as mixing the types of drug goes, you would have to ask your pharmacist about that and then based on what he tells you, ask your doctor. Pharmacists are much better educated about drugs than doctors so they are a good place to get answers to that kind of question.

Debbi said...

Hello please help...my mum is type 2 and I am reading all these posts where people are quoting stats and I don't understand any of them. Her doctor is useless and doesn't tell her anything and hardly ever tests her. She is on 850mg metformin each morning and suffers terribly with nausea and diarrhoea. The doctor does absolutely nothing to help her. Can you please explain the basics and what the stats mean, so I can try to help her manage it.
Many thanks

Jenny said...


You need more information than anyone can give you in a web posting. A book like The First Year: Type 2 Diabetes by Gretchen Becker or my own book, Blood Sugar 101 will explain the concepts you need to know to understand what people are talking about online.

Both books can be found at Amazon or ordered from anywhere around the world from The Book Depository.

Anonymous said...

How long does it take Metformin to start to lower your blood sugar?

Jenny said...

If metformin is going to lower your blood sugar, you should start seeing an impact within a few days and by two weeks you will see the full effect.

If metformin has no effect, it may be because you aren't making insulin properly rather than that you are insulin resistant.

Dave said...

I have been taking 1000mg/day Metformin for a year now and still have a high A1C. I am not convinced that the Metformin is doing much good. Is there a test that I can do at home or some lab work my Dr can order for me to verify if my high BG levels are because that I am not making insulin properly or because I am insulin resistant?

Jenny said...

1000 mg of metformin is a low dose for a male adult. Typically people take 1500-2200 mg/dl. So you might ask your doctor why he is giving you that low dose.

Beyond that, the C-peptide or fasting insulin test might show if you were producing very low amounts of insulin. Unfortunately, that test isn't diagnostic until a person is producing almost no insulin at all.

I would suggest trying the technique you will find at http://bloodsugar101.com/how.php

It is often much more effective than any drug. I hear from hundreds of people who have found it extremely helpful in regaining control. It works very well with metformin.

Anonymous said...

If you eat lunch at 12 and want to take your metformin at 2 pm., can you just eat a small snack (like cheese) with it? Currently I take at dinner but if my digestive issues don't resolve, may want to try taking at 2 pm

Jenny said...


The important thing is not to take more than the full dose you were prescribed during a 24 hour period. Beyond that, you can experiment to see what works for you.

Anonymous said...

I just didn't know if I needed to eat something with it versus taking on an empty stomach. Right now my full dose is 500 and I am supposed to increase to 1000 gradually.

Jenny said...

The only reason to take metformin with food is if it upsets your stomach when you take it without food. Taking it with or without food doesn't affect its activity.

Unknown said...

I was diagnosed with diabetes 2 years ago, I have been on Metformin 1000 mg 2 x a day. Last week my doctor switched me to 2000 mg Metformin ER once a day. Does it take a while for it to start working as yesterday my sugars were 7.8-16 all day and no matter what I did I couldn't get them lower. When I was on regular Metformin it went as low as 2.8 every day. Now I'm on Glumetza ER. MY A 1 C test came back at 6 but he said its combined with really low lows and very high highs. This is my 7 th day on the ER GLUMETZA just wondering if I should wait or switch back. The only reason he switched it was at my request I just felt like it would be easier to wake up take my pills and not have diabetes rule my life. I wouldn't have to think about it the rest of the day.

Jenny said...


It is very unusual for metformin of any kind to cause hypos such as what you describe. Are you also taking a drug that provokes insulin secretion for a long time (8 hrs or more) like glipizide or glibenclamide? If so, the solution might be to ask your doctor about a shorter acting insulin stimulating drug like repaglinide which is only active for a few hours after a meal.

Another alternative would be to ask if you could use fast acting insulin at meals rather than any drug that stimulate insulin production. That would make it far easier to keep those meal-time highs under control.

Certainly, the blood sugars you are seeing now are unacceptably high, and after a week on the Glumetza ER you should be seeing the full effect since you were already on metformin. So it looks like this version doesn't work for you.

Unknown said...

I am taking gliclazide modified release tablets, it seemed to be working for about 4 days, then I kind of thought that it was my stress level that was doing it and then, when I worry about that plus the other added stress of my life it seems to make it worse

Jenny said...

Tracy, That's your problem. Those pills cause insulin to be secreted even when you don't need it. They are notorious for causing hypos.

Talk to your doctor about cutting back on the dose of the gliclazide because metformin on its own doesl NOT cause hypos. However, because metformin blocks the liver's ability to dump glucose, it makes hypos caused by other drugs much worse.

Unknown said...

Thanks so much, so do you think I should stop taking the glicazide until I can get to my doctor? I can't get an appointment for 6 weeks its ridiculous. How long would it take to get the drug out of my system I'm on 30 mg once a day

Jenny said...

I am not your doctor, so I can't advise you on the specifics of what drugs to take. Doesn't your doctor have a phone line where you can call about problems like this one?

Unknown said...

Unfortunately no, I have to wait 6 weeks, I'm one of the lucky ones here, there are a shortage of doctors here, people have been waiting 3 years or longer for a family doctor, 1/3 of the population of the city don't have a family doctor. Thank you for the information, I appreciate someone who knows what they are talking about, I just feel like diabetes is ruling my life and I want it back, it's so discouraging

Stephanie Catibayan said...

I don't know why but I can't take metformin on a full stomach. I have to time my dose 2 hours after eating and 2 hours before eating. Anything else and well....Someone install the seatbelt on the toilet.

Unknown said...

Auntie J:
2 years ago Metformin was prescribed; it made me so deathly ill, I could not continue. Have been careful with diet and BS tests range between 7-9,
Careless with diet for past few months and BS raised to present 9-11; not good! Have new prescription for Metformin and because I already have IBS, dizziness, short of breath, heart murmur, queasy stomach; am scared to death to start Metformin. Any suggestions? Would low dose of insulin be easier to take and help the overall situation? I am in my 90's and think this may be very hard to take. I just discovered your column; find it informative and so helpful. My thanks!

Jenny said...


Metformin could be a problem for you. You need to discuss your concerns with the doctor who prescribed it, or, if you can't get through--as most of us can't nowadays--with his or her nurse.

If you are in your 90s any drug might be hard to metabolize, so make sure to start with a very low dose --no more than 500 mg and only raise it after a few days if you can tolerate it. That is how metformin should be started for most people, but no all doctors seem to be aware of that.

Unknown said...

I being taking 500 mg of metformin 2x a day and still my sugar at night is 263 should I take one more pill before bed to Lower it even I have nothing to eat.

Jenny said...


No dose of metformin is going to be enough to lower blood sugars as high as what you are reporting. You should talk to your doctor about whether you should raise the dose, but even if you do you will need to do more to bring your blood sugars down to a level that won't damage your organs.

I would suggest that along with the metformin you try the technique described here: How to Lower Your Blood Sugar.

If that doesn't work talk to your doctor about starting insulin. Research has shown that people with Type 2 diabetes who use insulin, even if only for a few months, will end up in much better shape years later than those who don't.

Jan said...

Jenny, I'm newly diagnosed with Type 2, after being borderline for the past 10 years. I also have metabolic syndrome, running the gamut with hypertension, hypercholesterolemia, weighing nearly 300 pounds on a 5'2" frame, and a stomach that makes me look pregnant. I'm 59. My mother died at 63 of diabetes complications. She was diagnosed late, too. She was very thin, though. She took her insulin shot and didn't eat, and she went into a diabetic coma and died 4 days later. The only diabetes treatment I'm on is metformin ER 500 mg once a day. My recent labs showed fasting glucose 107 and A1C 6.5. Since being on the metformin ER, I find that I feel hungry shortly after eating. Also, I wake up during the night ravenously hungry. Thus, I'm not getting much sleep. My doctor says it really doesn't matter which time of day I take the metformin, as long as it's consistent. Is it common for the metformin to cause a person to feel famished after eating and during the night?

Jenny said...

Jan, That isn't a usual response to metformin, however, it is possible that the metformin is lowering your blood sugar below the level you have grown used to, so your body is having a false hypo. (Discussed HERE).

If that is the case, the problem should go away as your body adapts to lower blood sugars.

You can take a look at your blood sugars with a meter to see how they are moving after you eat. Sugars that rise and then drop swiftly often cause hunger, without regard to how high they are. People with high sugars that stay high are less likely to feel anything related to blood sugar than those whose sugars shoot up and drop down. But the high sugars that don't change are the ones that damage our bodies.

What do you see with your meter 1 and 2 hours after eating?

Jan said...

Thank you, Jenny. My doctor said it's not necessary for me to start testing this early in my new diagnosis, since my numbers aren't that high. I can't afford the testing strips, as my insurance won't cover them. It only covers the testing unit, but not the strips.

Anonymous said...

No matter how much research I do, I always end up back on this article/blog. I know you wrote it ages ago, but you really have a singular talent for discussing the things people want to know most!

I've been on 1000mg Metformin XR for several years for insulin resistance/PCOS. I take them before bedtime, without food. Now that I'm 24 I plan to finally increase to the typical adult dose of 1500mg XR.

I currently take 2 500mg XR at bedtime, since it's easiest to be consistent that way (I sleep in on weekends when I can, don't always eat at the exact same time, etc). The idea was to simply begin taking 3 500mg XR at bedtime, but I've read in several places that Metformin isn't as effective when taken without food. The pamphlets that come with the medication do say to take with food, but I always assumed that that was to avoid stomach upset, not because the medication would be less effective without it! Have you heard any indication either way of Metformin XR's effectiveness when taken without food?

Jenny said...

I know of no reason why taking metformin with food would make it more effective. The advice to take it with meals is indeed because it can irritate an empty stomach.

Unknown said...

Hi, I am so glad that I found this blog!! I need some advice. Here is my dilemma. I am 44 years old, female and I weigh 278 pounds. I was diagnosed in 2003 with type 2 diabetes. Over the years my Metformin and Glyburide has increased. I am on high doses of both currently. 1000mg Metformin with 10 mg of Glyburide with my 1st meal, and 1000mg Metformin and 10 mg of Glyburide about 8 hours later with a meal. I must have reached a plateau because my blood sugars have gone way up. No matter what I eat, it is hard to keep my sugars under 200. So, about two weeks ago, my doctor ordered the Levemir insulin pen for me to add to the treatment plan. I take 15 units before bedtime of the insulin. I don't notice a change yet. Not sure how long it may take to reap the benefits of adding the insulin.... My CRP (inflammatory marker) is VERY high also. Is there any thoughts, advice that you can give about the timing of my pills? My waking sugars seem to be the highest. I read somewhere that overnight glucose is produced at a high rate. Also, I have terrible IBS. I want to start probiotics, but I am scared that it will cause me to develop lactic acidosis. Does anyone know if it is safe to take probiotics with Metformin?

Manuel s y M said...

Hello, have you heard if dry mouth can be a side effect of metformin?, im 4 weeks into metformin, my fasting levels are in the 90's and postpandrial do not rise above 140, im taking 1500 xr in the nights, not taking anything else, however doctor says its anxiety, i have no saliva at times, it is too thick and sometime i cant even form a spit, it started at the same time i started on the metformin, its on and off.

Jenny said...

Disturbances of taste are a known side effect, but that refers to tasting an odd, often metallic taste. I have not heard of decreased salivation.

Jenny said...


Sorry for the late reply, but Google failed to notify me of your comment. The dose of Levemir you are on is extremely low. Most people with Type 2 who are your size need 100 units or more to see an impact. You need to talk to your doctor about slowly raising your dose until you find one that is effective.

It's important to remember that levemir will only lower your fasting blood sugars. You would need a fast acting insulin (Novolog or Humalog) to cover the spikes after a meal.

If you can see an endocrinologist, they would be more likely to be able to help you get the doses of these insulins right, which takes some work. Family doctors are often not very aware of the proper way to dose insulin.

Jackie said...

I was just diagnosed with insulin resistance and was prescribed 500 mg of metphormin hcl er. My prescription says take 2 tablets two times a day. Thats 2000 mg to start. Is that ok/normal? It seems that is odd. I just started today but only took 1 with breakfast and one with lunch. I figured 1000 mg is enough to start and am thinking of doing that for a week then increase the dose. But maybe I should go ahead with the 2000 per day and get all of the side effects out of the way. And my prescription is a 90 day with 3 refills. But some of the comments scare me into taking 2000 per day at the start. Any feedback would be great

Jenny said...


Some people experience diarrhea the first few days they start Metformin, which is why doctors often start people on small doses. However, some doctors seem to forget the part about working the dose up to the level that is effective, which is around that 2000 g for many people. I hear from a lot of people who were put only on the starter doses, which won't do anything, and assume that the drug doesn't work. When it "doesn't work" doctors immediately put them on much more expensive, much more dangerous drugs.

So it's good that your doctor prescribed the full dose. If you aren't having digestive issues, there is not reason not to take the full dose. If you do, no harm is done by staying at a lower dose for a few days until your body adjusts. But you should try to get to the dose the doctor prescribed within a week or two if possible.


Unknown said...

Hi & ty in advance for your advice. I have been a T2 diabetic for 8 years, taking 1500 metformin in am and 1000 at night. My fasting BS is always between 140-150 and then stays around 100-120 all day/night. Do you believe that taking the night time dose at dinner time, rather than 10 pm would help with my high fasting BS? For awhile, with high A1C, I was prescribed glimepiride to take in a.m. but my BS would go down within hours to the 50's and I would get sweaty, shaky, etc. and my dr. doesn't seem concerned! I stopped taking the glimepiride ( my own decision ) and started for the past 4 weeks eating 3 times a day and 2 snacks and watching my carb intake. I am about 30 lbs overweight after losing 10 lbs this past month and still losing. My fasting still is high as I said, but not 170-180 as it was a month ago so I feel I must be doing something right?? And I no longer have real low BS since off the glimepiride. But, I still cringe at my fasting BS number every morning. Do you believe it would be more beneficial to take the 2 500mg metformin around dinner time or doesn't it make a difference? Would even taking 2 500mg instead of 3 in the am, along with 2 around dinner time and then 1 at bedtime be a possible good thing? I FINALLY am getting serious about my health and see positive results but want to do what's best for the fasting BS. Thank you again for any advice you can give.

Jenny said...

First of all, congratulations on taking steps to improve your blood sugars! A couple thoughts. If that is extended release metformin, there's no reason you can't try changing the timing of your metformin dose to see what happens. Just be sure that you don't take more than that 1000 mg total during 24 hours. I.e. Move your dose forward in time, but never back.

If it is the fast acting plain metformin, two at once might be tough on your digestive tract.

Second, 2 500 mg metformin's is not a full dose for most people. Ask your doctor if he could increase it to three 500s a day and see if that helps.

Alyscupcakes said...

Hey Jenny!

You have such great advice, I was wondering if you could help me as well.
My doctor wants to put me on metformin to reduce my high insulin and help my hypoglycemia.
But I'm actually very confused by this, my fasting blood sugar is 75-95. My postprandial blood sugar never raises above 100 unless I eat very extreme amounts : over 1000 calories (bs 114@1hr), consume 100g of simple sugars (bs 134 @1hr).
I start to experience hypoglycemia as soon as 30 minutes with in eating and will be at a lower blood sugar at the 1 hour mark, then before I ate. But I do frequently go below 70 at the 1 hour and 2 hour postprandial.
My average 2 hour post meal blood sugar over 100 tests is 79.

I'm not sure how metformin will lower my insulin if my blood sugar is already on the low end? Nor do I see this helping with my horrible experiences with hypoglycemia.

Am I missing something here?

(I'm already on omeprazole to slow digestion)

Jenny said...


Your doctor is thinking that the metformin might reduce your insulin resistance and that would lower the amount of insulin you secrete when you eat. If it did, that would improve your hypoglycemia.

It's worth a try. Give it a try for a few weeks and see if it works. Metformin takes about 2 weeks to fully kick in.

The one concern is that metformin also blocks the liver from dumping glucose to raise blood sugar. But since it doesn't seem to be doing that right now, perhaps this isn't a concern.

Unknown said...

Help please,

I have recently been diagnosed with T2, and have been taking metformin for 2 months now.
I take 500mg at 11am after cereal (I wake up late due to sleep apnea), and as I have an evening meal at 8pm, I force down a sandwich at 11pm before having my evening 500mg dose.
I don't know if I am eating enough or at the correct times, all I know is I have been told to have it with food.
Any clarity, much appreciated.

PRIVATE said...

Hi Jenny, great blog and very informative.
I started Metformin about 4 years ago 2000mg then dropped to 1500mg after a year.
Just last year I started to increase my carb intake, but felt good when I increased it, wasn't feeling sick or anything, but now I have put on weight again and the extreme hunger is back with a vengeance. I am waking up in the middle of the night starving.
Just a few days ago went back to 2000 mgs and I actually slept during the night without waking up hungry. My question is, how would I know if I'm now fully diabetic or still prediabetic since my A1C is 5.2 and fasting is 4.5, but still have all these horrible symptoms ?? This is so confusing.

Jenny said...

Private, Get a blood sugar meter and test your blood sugar 1 and 2 hours after eating. If you see it going up steeply (say over 9) and then dropping back fast over the next hour, that could explain the hunger.

Alternatively, if you see your blood sugar dropping down below 3.9, that could also explain the hunger. You can experience that hunger without reaching diabetic blood sugar levels if the blood sugar is dropping too swiftly or going too low.

PRIVATE said...

Thank you for your quick response.
I also have rashes on the side of my body again, near my breasts and my feet go from hot to cold.. insulin resistance has gotten worse and have had to drastically cut down carb intake.
I am scheduled to see a doctor soon, where I will check fasting insulin, and I think I should ask they check c-peptide as well...
I'm not sure that pre-diabetes (insulin resistance) can cause all these problems.

Unknown said...

hi good day! am so thankful for this..yo are such a blessing! I've learned a lot from you.. I'm just worried for my father..he's taking 500mg metformin janomet 8am after breakfast then 8pm after dinner.. he feels good anyways, but his fasting blood sugar next morning was 170mg/dl..what would you think is the best way to do to lower his BS? does he need also to take BS 1hr, 2hrs after meal? what must be the normal range then? all he wants is to have a lower fasting blood sugar in the morning in preparation for his medical employment..thank you so much for your kindness! God bless you.

Jenny said...

cc cc, Your dad should try the technique described here: How to Lower Your Blood Sugar.

If he sticks to it for a few weeks it should lower his blood sugar a lot.

That fasting blood sugar is high enough to damage his body over time, so he should not just stop worrying about it once his employment situation is taken care of.

LilM said...

Dear Jenny, thank you for all this helpful info! I'm wondering about how to monitor the efficacy of Glumetza when taking it for Pcos. I was diagnosed with Pcos 10 years ago (when I was 16) and they put me on the bc pill. 5 years ago they switched my pill brand and I gained a ton of weight. My obgyn switched me to another one after a year, plus 500mg metformin once a day. I was in agony for a couple months with stomach pains and bathroom issues but just waited it out until I got used to it. About 2 years later, stomach problems were unbearable (always bloated and in pain) so I went to get checked out and got switched to Glumetza, but also turned out I have hashimoto's (autoimmune thyroid.) I went gluten free and then a year later, dairy free. Pain subsided but bloating persists. Still not on any thyroid meds although my levels are at the edge. I'm still on the pill and the "baby dose" of Glumetza. A new obgyn recommends getting off the bc pill, as it is linked to insulin resistance and autoimmune issues. I'm afraid pcos symptoms will return after 10 years on the pill. I exercise regularly and am on a healthy gf/df vegetarian clean diet but seem to be gaining weight regardless (157, 5'6). When u go off the pill, I'm wondering whether I should up my dose of Glumetza since it seems nobody takes just 500 mg for pcos. Perhaps it will help regulate my cycle after coming off the pill... Any experience or thoughts with this? Since I'm not taking it for diebetic reasons, I'm not sure how to monitor its efficacy besides whether it will regulate my cycle or help me lose weight. Thank you!

Jenny said...

LilM, Unfortunately, I don't know how metformin is best dosed for PCOS. Your ob/gyn is the person who should be helping you with this.

LilM said...

Thanks Jenny. Unfortunately I have yet to find one who is well versed in insulin resistance, or an endocrinologist well versed in pcos. Any info about metformin and insulin resistance might help - thanks again.

Baby Cheyenne said...

Hi Jenny, I started taking Metformin 4 weeks ago. 1000 x 2 once in am oce in pm. With meals. My problem is acid burn in stomach. Is there a trick I can do to relive or rid myself of this? Will this get better? My doctor wants me to start Glipezide or Byetta. I feel Glipizde will ,ale me gain weight. I can not gain anymore weight. And Byetta does it replace what the Glipizide does? I don't get the. "OR" in this equation Also to achieve a A1C of 6 do my numbers need to be below 120 2 hours after meals? Thank you for any thing you can tell me.

Jenny said...

There's no trick I know of that can solve that problem except maybe Pepcid AC. Both glipizide and Byetta have some potentially worrisome side effects. Read about them HERE and HERE.

Ask if you can try repaglinide instead. It has a similar insulin-stimulating effect but it has a better safety profile and is less likely to make you ravenously hungry the way that glipizide does as it is only active for a few hours after eating, not all day.

Byetta also stimulates insulin secretion, but in a different way. Unfortunately, there is some evidence it might be very harmful to your pancreas over time.

It is different for different people what A1c you get with tight control because genetic factors influence how the A1c ends up. Some people will have higher A1cs with the same level of tight control. The important thing is that it is the actual blood sugar levels, NOT the A1c that cause the complications you are trying to prevent.

The A1c is a test that appeals to busy doctors who don't want to have to look at blood sugar logs, but it is not anywhere as predictive as actual blood sugar levels.

Anonymous said...

I'm taking 1000mg twice a day just started today. When should I take them so it doesn't go over the 2000mg in a 24 hour day

Anonymous said...

I'm on victoza and 1000mg twice a day of glumetza when should I be taking the glumetza as to not exceed the 24 hour thing. I just started it today and I feel kind of funny from it.

Katydid said...

I have to re do my eating habits due to weather changes. I find now when its extreme heat and Im in the house with the ac on I want to eat ..like yesterday..today I am paying for it with a high BG reading and waiting on my meds to bring it down..I will be up all night..1 other time this happened and I should have started working on it then. I find drinking ice water does help after taking Metformin w/ glipizide which is what I am on. I found time frames very interesting. It is very difficult to get consistant.

Jenny said...


Questions like yours should be asked to the pharmacist who provided the drug to you. There is always someone at a pharmacy who can answer questions about the drug.

Anonymous said...

Hi Jenny

I have been instructed to take Metformin 500mg once in the morning and once in the evening but am finding that when I wake up I am getting mild to moderate hypos. Have you heard of anyone else getting this reaction, assume my BS goes too low during the night though I have crackers and cheese before bed! Many thanks.

Jenny said...

Alison68, Are you taking any other medications? Metformin can make some insulin stimulating oral drugs much more powerful which will cause hypos.

Otherwise, that small a dose on its own shouldn't be causing hypos.

Unknown said...

Just wondering, Should I have been given something to monitor my blood sugar? VA Dr. has given me nothing. I have been taking 500 mg 2x daily breakfast and dinner, I have blurry vision (right now and a lot), dizzy lightheaded and hungry all the time, I only see my PC/DR. like 2 times a year.

Jenny said...

Melissa, If you want to avoid diabetic complications a meter and strips are your most powerful tool. But they are expensive, so the VA may only provide them to patients who demand them. Call up and tell your doctor you want the prescriptions for both. Then when you get a meter, use the technique described at the link below to lower your blood sugar. It works very well for most people.

How to Lower Your Blood Sugar

Kammie1 said...

Hi there I'm a 23 year old women and have been taken metformin for a week on one dose of 500g and today I have to start taken 500x2 but I was half sleeping this morning and have taken them at the same time I'm just worryed is that ok? I'm ment to work my way up to one 3 times a day x

Jenny said...


If it is plain metformin you are taking, taking two at once might be hard on your stomach, but nothing serious will happen and it will wear off in a couple hours.

If it is the extended release form (ER) then taking two at the same time is completely fine.

Kammie1 said...

Thank you Jenny just got a bit worryed I have been ok so far just feeling very tired lol I take metformin because I have polycyclic ovarys x

Unknown said...

Hi, i started to glimpiride half mg, metformin 250 mg, per day, bsl come down but Feel empty stomac, some pain in stomac, after 4 days, felt more thirsty, lot urine, that time my pp was 208 bsl. But Side effects of morfine arised, and how much time metformin stay in body, how is decreasing, pls guide.

Jenny said...

Some metformin stays in the body for about a week. However, you are taking a very low dose which probably wouldn't have much effect. It takes a dose of 1500 to 2250 mg/day to affect most people.

Unknown said...

Took first dose of metformin yesterday. Experience stomach discomfort and diarrhea. I usually have a meal replacement shake for breakfast. Morning blood sugar ranges between 115-128 I take 500 mg of metformin once a day. When is the best time to take metformin am or pm

Jenny said...

Wanda, Go back and reread the post. It should answer your question.

Lisa T said...

I am writing for my husband. We are Americans living in Zambia, Africa, where healthcare is not the best. I have been testing him, and it appears he may need to start taking Metformin 500mg, which I was able to purchase OTC. My concern is that he takes 50mg of labetalol for his bp. I have read the concerns of these being taking together. What can you tell me regarding the drug interactions at these low doses? I appreciate any help you can offer. Thanks

Jenny said...

Lisa T, You need to speak to a doctor or pharmacist about this issue, ideally one who can access your husband's medical records. It would be wrong to take advice from anyone on the internet who isn't familiar with the specifics of your husband's medical condition.