Metformin for Prediabetes

Prediabetes is, for many people, a confusing condition. It’s not quite Type 2 diabetes — but it’s not quite nothing, either. So how concerned should you be about it?


For years, the jargon-filled names given to this condition — impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) — may have made the task of taking it seriously more difficult. But in 2002, the American Diabetes Association (ADA), along with the U.S. Department of Health and Human Services, inaugurated the term “prediabetes” to convey the likely result of not making diet or lifestyle changes in response to this diagnosis. In 2003, the threshold for prediabetes was lowered from a fasting glucose level of 110 mg/dl to one of 100 mg/dl.

Then, in 2008, the American Diabetes Association (ADA) began recommending the drug metformin for some cases of prediabetes — specifically, for people under age 60 with a very high risk of developing diabetes, for people who are very obese (with a body-mass index, or BMI, of 35 or higher), and for women with a history of gestational diabetes. The ADA also said that health-care professionals could consider metformin for anyone with prediabetes or an HbA1c level (a measure of long-term blood glucose control) between 5.7% and 6.4%.

But according to a recent study, metformin is still rarely prescribed for prediabetes. The study, published in April in the journal Annals of Internal Medicine, found that only 3.7% of people with prediabetes were prescribed metformin over a three-year period, based on data from a large national sample of adults ages 19 to 58. According to a Medscape article on the study, 7.8% of people with prediabetes with a BMI of 35 or higher or a history of gestational diabetes were prescribed metformin — still a very low rate for the highest-risk groups, in which evidence for the benefits of metformin is strongest. It appears that most doctors simply aren’t following the ADA’s guidelines or aren’t aware of them, as they relate to prediabetes.

As we noted here at Diabetes Flashpoints in a 2011 post, both metformin and lifestyle intervention programs have been found to be effective at slowing the progression of prediabetes to Type 2 diabetes — with lifestyle intervention found to be more effective but more expensive. While there is debate about when and whether it’s best to prescribe metformin or a lifestyle program for prediabetes, it’s unlikely that more than a handful of the participants in the recent study were participating in lifestyle programs, instead of or in addition to taking metformin.

What’s your view — why do you think more doctors don’t prescribe metformin for prediabetes? Do the ADA’s recommendations reflect a willingness to prescribe drugs without first giving lifestyle interventions a chance? Given the choice, would you rather take a drug or participate in a lifestyle program for prediabetes? Do you think people who are prescribed a drug, like metformin, are more or less likely to make lifestyle changes that could help their prediabetes? Leave a comment below!

Want to learn more about this popular diabetes drug? Read “Diabetes Medicine: Metformin,” “Metformin: The Unauthorized Biography,” and “Metformin Smelling Fishy? What You Can Do,” then take our quiz, “How Much Do You Know About Metformin?”

Learn more about the health and medical experts who who provide you with the cutting-edge resources, tools, news, and more on Diabetes Self-Management.
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  • Roberta Workman

    Metformin killed my husband’s kidneys. Think about that before you jump on the metformin bandwagon. He’s stage 4, which is one step from dialysis and then death.

    • lonni clayton

      Yep same thing happened to me Roberta, one week of metformin and I was in kidney failure.. Fortunately I was work in the medical field and knew what was happening so stopped taking it immediately. But i am still in moderate kidney failure.

  • Diane

    I definitely thought the Dr. could have and should have given me something to prevent the diabetes diagnosis when he kept telling me the past couple of years that I was “borderline.”

    • Judy Hoyle

      I fill the same I should have been started on Metformin long before I was so now I have neuropathy in my feet because of it.

    • Judy Hoyle


  • Natalie

    I was diagnosed with Type 2 in January 2000. Metformin was prescribed…..and by the end of January it had shut down my kidneys. Insulin has worked great since then. But the damage isn’t reversible….I’m still stage 3.

    • Judy Hoyle

      Thank you for sharing. May the peace of God and Blessing be upon thee.

    • Jenny

      If you don’t mind my asking, how many milligrams were you on? I just started today on 500mg/day for prediabetes and dismetabolic disorder but now I’m nervous.

  • K Orville Berger

    I was started in 1980 with Diabeta. Was on it for ten years. In 1990, Metforman and Actos was prescribed. In 2002, both were discontinued and full insulin therapy adopted. So far, according to blood work including kidney function, everything is acceptable. I’m either durable or lucky. I have a rather consistent A1C value of 5.9%. I’m a T2 that produces no insulin.

  • Martha Taylor

    Due to my family history my Doctor prescribed metformin when I was pre-diabetic. I am 63 and have been on it for 7 years. I made one change in my diet. I no longer drink soda. I drink sucralose sweetened flavored sparkling water instead. My A1C has been in the 5.25 to 6.0 range. I feel great and all my liver and kidney functions are normal.

    • Judy Hoyle

      Great news!

  • I wish I had been given it when I was prediabetic…

    • Judy Hoyle

      Me too.

  • Deborah

    I never was diagnosed as prediabetic, my first diagnosis was as a diabetic so in my case no. However, my roommate was diagnosed as a prediabetic and she was prescribed metformin.

  • Lisa

    I’ve heard Metformin causes A-fib in some people. A couple of years after my husband went on Metformin his heart went into A-Fib and cardioversion was not successful. My status is being evaluated next week for prediabetes and I’m not interested in going on Metformin to prevent diabetes. I’ll exercise myself to death first to keep my sugar controlled.

    • Judy Hoyle

      Thank you for sharing that information first I heard of it.

    • SailorMom

      Metformin is supposed to prolong life, like a fountain of youth. How can they claim that if it causes A-fib. It’s been six months since your post, how are you doing? Well, I hope.

    • Joseph

      Metformin does not cause A-fibb. A-fib is the most common heart arrhythmia in the general population, not likely that metformin caused it. In fact it is just the opposite, Metformin prevented A-Fibb in recent research study for diabetics. Check your source, Metformin DOES NOT cause A-fibb. I posted the web address to the research here.

  • miraclecomposer

    I begged the doctor to just give me the metformin because it prevents diabetes instead of insisting on three months of every day testing proving I had diabetes 1st before giving me any metformin!

    • Judy Hoyle

      I went through the exact same thing.

  • martialartsfan

    I started on Metformin during pre-diabetes, and it has had no effect on my rising glucose and A1C. I’m now using Glipizide, also, and hoping for the best. I feel 10 to 20 years older than I did 2 1/2 years ago.

  • Miss Caroline

    I have had Type II Diabetes for 10 years and have taken Metformin the entire time. My last A1C was 6.3 and blood sugar runs around 135, fasting. If I had been given Metformin (and a little more diabetes information) 10 years ago, I might not have it today. The guidelines for pre-diabetes and diabetes keep changing, so with the new information, with a 6.3 A1C, I should be pre-diabetic now.

    • Judy Hoyle

      Miss Caroline I fill the same way.

  • Cassie

    I have full blown diabetes because my doctor didn’t think I could get it because I’m under 30 and short.

  • zainab Majid

    Changing in lifestyle like worries , stress, sleepless anger etc change glucose level in the body . i think first patients should monitor their blood sugar level , maintain stress worries and a good diet for period of time before taking any antidiabetic . checking fasting glucose level as well after breakfast and other meals for a week and taking care of mood changing .

  • Segundino S.Ladura

    Is there any side effects on metformin?

    • Tina Marie Gillispie


  • Jean

    I was diagnosed with pre-diabetes & my doctor wanted to put me on metformin. I didn’t want the RX & immediately went on a very diabetic friendly way of eating. I lost Weight & my A1C was within normal range. I maintained this for over a year & then started eating the carbs again. I have other health problems including thyroid issues. I have no energy & its a lot of work eating healthy. My A1C was 6.5 in January. I see my Endocrinologist in August & he will want to put me on Metformin. I can’t &/or wont eat right on my own so I will probably go on Metformin.

    • Lil25

      See, this is the reason why I think more people should be on Metformin for prediabetes. Relatively few people can sustain lifestyle modification forever. There’s absolutely no reason you can’t change your eating and exercise habits while you’re on Metformin! Why not do both?

  • ari

    I’m 18 with PCOS and prediabetes. I’m 5’5″ and weigh 170 despite the fact that I eat healthy and walk several miles a day. I have celiac disease and I’m lactose intolerant so I can’t really eat most foods that are bad for me; I actually follow a relatively strict diet given the wide variety of choices at the assortment of dining halls on my campus. I eat about 6-10 servings of vegetables/fruit (way more leafy greens than anything else; fruit is only in the morning when I don’t feel as bad about sugar intake). I don’t drink soda or juice, only soy/almond milk and water. I walk several miles a day, a good part uphill because my campus is hilly.
    I can feasibly change nothing about my lifestyle because of the nature of being a college student; stress is inevitable and short of quitting I wouldn’t know what to do about that. even if I go to Cookout with my friends I don’t get food. at this point it’s slightly miserable even being around people during mealtimes, and I don’t want to be forced to restrict my diet even further if I get full-blown diabetes. I already have an autoimmune disorder and other stuff that makes my life really frustrating. I don’t need a chronic illness too if I can help it. my OB-GYN won’t prescribe metformin prophylactically but she told me to consult my PCP. I’m thinking about bringing some studies and asking for metformin because it doesn’t make sense to me to sit here waiting to become a victim of my family history when I’m doing my part.

    • Angi Gray

      Metformin at 500 mg 3x/day is considered appropriate treatment for PCOS; there is no reason you should not be on it.

  • Angi Gray

    Doctors need to take the whole picture into account. High fasting glucose is a problem with the liver and absolutely suggests Metformin should be prescribed. I begged my doctor for it when I was prediabetic with high fasting #s and he refused. Six months later, he diagnosed me diabetic (barely), despite changes to the way I ate – healthy to begin with – and gave me a glucose monitor which proved not only that I had a fasting glucose problem, but that my personal limit to keep my glucose in NORMAL range is very low (35 carbs max in any 4 hr period). Also, the fact that I wasn’t eating breakfast and rarely lunch was causing high #s all day. Metformin + eating regularly and MORE caused me to lose 20 lbs rapidly, but I still need a higher dose of Metformin so I can loosen up a bit on the carb restrictions for a more rounded diet, and he doesn’t want to up it. It’s so frustrating!!

  • sam

    I am trying lifestyle changes instead. While taking metformin my blood sugar rose and I felt completely dried out. I feel better since I don’t take it and my blood glucose is lower.

  • Jenny

    I took low dosage500 mg per day. I watch what I eat, do moderate exercise. Good thing I lost 10 pounds. I cut back sweets, I still eat it- just few bites. Actually fruits are the one raise my blood sugar, cannot have a whole peach any more.

  • Michelle

    My blood sugar levels are all over the place I eat more food now by taking melformin than I did before. I work out two too three times a week I hate taking this durg.

    • Sherri

      If you are type 2 try a ketogenic diet. Look up videos on you tube about ketogenic diets. I feel great following it.

  • Narsbars

    Did almost the same. Started at 234lbs and sedentary. I got an A1C of 5.9 and got scared straight.I started a strong diet.
    60 days later 1500mg metformin a day, no sugar, nearly no carbs, lots of supplements. Still sitting on my butt and not exercising but down to 196. Until I dropped milk altogether I was still over a 100 fasting. Now I am seeing 84 and 87 in the morning. Trying for 80.

  • Narsbars

    Started at 5 10, 240 pounds, late 60’s male. My doctor showed me an A1c of 5.9, then I bought a meter and consistently tested over 100 up to 134 fasting. I have been losing 10lbs a month, taking 3×500 Metformin per day. Of course no sugar, low carbs. Finally getting to where I can exercise again. I intend to hit the treadmill 30 minutes a night.
    My fsg is now hovering at low 90s to 104 but even three hours after a very low cal dinner (400 calories) my glucose was still 154. I think my remaining fat, now I am 190 and down to a 40 inch waist is still a huge contributor. Planning on getting to 155 before going off the diet somewhat because you carry nearly 5lbs of food in your gut when you eat normally.
    I just wish meters were truly accurate.

  • Guest

    Risk of bladder cancer. Not good for prediabetes. Drug list on Mayo clinic

  • John Sakariassen

    Im getting prescribed tomorrow through my primary care doctor, but yes the lactic acidosis warning is something everyone should see and it does make me worry.

  • Linda Miller

    Bad advice. The metformin could put her in the hospital.

  • Alexandra Amato

    I’m 21 years old and have recently found out that I am pre-diabetic. They put me on met forming. I’ve only been taking it for about a week. The dr. Says she would want me taking 4 pills eventually. Right now i take 2 pills and try to eat with them otherwise the side effect has me in the bathroom. How long should I wait to start taking more? How long will this take until I start feeling a difference? I’m sorry if I’m commenting on someone else’s post I do not know how to make my own post.

  • Kate Mana

    Does anyone know if 250 extended release would be beneficial? I was taking 500 ER once a day and it made my eyes and mouth so dry and increased urination so much I had to stop

  • Texan_in_Thailand

    Bite the bullet and go through the hassle of getting another doctor, as this one is doing you no favors at all. (I doubt that it would help to tell her so, but she is, in fact, not honoring her Hippocratic oath to put the health of the patient first.)

  • DDM1

    Canada might do. I also get meds for my pets from Canada without vet cost for Rx if Rx needed in US for meds.

  • Michelle

    Hi i am border line diabetic. Tried excercise and food but cant seem to loose my weight if anything im getting bigger, joints aching feel tierd. Should i ask about metformin

    • Sherri

      Look up ketogenic diets. That will help you and the aching will go away.

  • Guest

    Any drug should be a last resort. Only an AIC of 6.5 or higher. It kills all the B12 in your body.

  • PD

    My preference would be to try lifestyle change for 3 months, get an A1C result, and if its not working then put me with a nutritionist to see if I’ve misunderstood something on the nutrition/lifestyle route, then another A1C in 3 months and if still bad, put me on metformin.

    I have pre-diabetes, for years now my doctor just told me to avoid white bread, rice and obvious sugars. I’d already been doing that & expressed as much. I cook my own food, mainly lean meats and veggies, I was consuming brown rice which he never indicated I should avoid or limit the quantity there. Thanks to ADA website, I’ve now cut back to never more than half a cup per meal because now I carb count- something my doctor never recommended because he doesn’t believe me when I talk about my diet, perhaps because my cholesterol was also weird (high on LDL & HDL in addition to low b12).

    It’s proved a very frustrating experience. Most advice is lose weight, but at 118lbs, I’m not really a candidate for that.

    Being in my early 30s, it’s young to be progressing down this path. I am stuck trying to figure out what I’m doing wrong on my own from the ADA website because the doctors quite frankly don’t take it seriously until you are actually diabetic, and don’t listen when I say that I don’t eat white bread, rice, fast food, soda or candy. It took a night in the ER with some symptoms they were suspicious was diabetes to even get the A1C, this is after bad fasting blood glucose test outcomes.

    And I’m not sure if I’m succeeding because my doctor doesn’t want to provide regular A1C tests.

    • I am also in this situation. I have spent the last 3 months doing a Ketogenic diet, which I encourage you to look at. I basically avoid sugar/carbs totally. At most 10 – 20g of carbs per day. If you stay under 20g your body enters a state of ketosis where you generate ketones and your body starts burning fat for energy instead of carbs. Just remember that you get far more energy from fat then from carbs. 1g of Carbs = 4 calories, 1g of fat = 9 calories.

      I avoid all products with carbs, which means yes I have a fewer meal options, but I tend to eat chicken (thighs/breasts) crock pot style with frozen asperygus/broccoli. I don’t drink milk as it has sugar, I have made several life style changes.

      In Nov. 2016 I had blood sugar A1C of 8.6 and a daily reading of 280 on my finger tests. No I average 80-140 for low/high as of the writing of this. I am getting my A1C done again this month and hoping its gone done a lot.

      The few things i will say about keto dieting is, you do not have that burst energy that you get from carbs/sugar. But I have a buddy that is a hard core athelete and after we are done at gym he will be completely exhausted for the day where as I find myself after about 30 – 60 minutes of rest able to do more activity. This is without eating anything since fat burns longer and slower then carbs its amazing for endurance and recovery. There are MMA fighters that do this year round for that, a lot of distance runners also use this diet.

      The only warning I have had so far on this, do not take ketone pills. Diabetics have kidney issues some times and taking ketones stress them a bit more then normal and it could hurt you.

      If you want some great ideas on food and how/what to buy from the store, email me and I’ll try to help out as much as I can. I have spent probably a few hundred hours in the last months reading about this diet and how to make it work the best way possible for our situation.

      • Christiane Marie Blackwood

        I’m interested in your food ideas and such

    • Victoria Quintanilla

      Get another doctor. Immediately. This one is not helping you manage your own health, which is what he/she has taken an oath to do. I have been at a1c 5.9 for at least a year and a half doing all the things you’re doing. My primaey care physician says “my numbers look good” and will not prescribe metformin until I hit 7.0.

    • Lil25

      I would seek further testing with a doctor who is a real expert in diabetes. At your age and with your history, I’m not certain you’re purely type 2. There’s actually a slim possibility that you could be LADA.

  • Pam

    I believe that when someone is pre diabetic they don’t really realize how it affects them as they have pushed there health to another level and speaking from my own experience I believe they need help like taking metformin. I believe you feel the difference and then once you start a life style change it makes you feel so much better that you try harder. At first I believe you need the meds as well as life change. As you know when you are pre diabetic you gain weight around the mid section and medication helps you break gluclose down normally so weight isn’t gathered around the mid section. Just that alone makes it easier to want to do better with life style changes. I played the game of no exercise, then exercise, eating better, exercise and still did not get where I needed to be but once I figured out it took all 3 eventually I was able to stop the use of medication and now I control myself with exercise and diet. I feel most should be put on medication first while they are making life changes. My doctors believe if I had not gone onto medication by now I would be a full blown diabetic. I believe they are right as I can truly feel the difference.

  • Sherri

    A ketogenic diet will help you. Look up videos on YouTube about ketogenic diets. You will be surprised at how good you will feel. Ketogenic diets help with cancer as well.

  • Rodney Dodson

    i just got my labs back and they say i am diabetic with 130 blood sugar and A1C6.7 at VA. i had blood done at about 3 month ago with no problems .how do you become diabetic in 3 months ,and will metformin hurt me if this is not right . i was not fasting and i have never tested high on blood sugar or A1C ever before. any in site

    • Rowena

      130 is okay right after a meal high in carbs. One test means nothing, especially a non-fasting one. You are not necessarily diabetic.

  • MG

    Look at Ketogenic diet with intermittent fasting ( less than 800 calories for 3 day at one meal /day) Then regular ketogenic meals – this works – after if you don;t care for keto switch to a whole food diet — See Joel Furhman. NO PROCESSED CARBS ONLY WHOLE FOODS….. SImple and easy!!! on Keto you will not be hungry!

  • shari dillon

    I don’t believe you to be a diabetic those are normal levels maybe you should see a different dr. or try the lifestyle changes

    • Kevin Criswell

      unless you are this person’s doctor you should NOT be diagnosing some one’s condition. This is an old post, but a very important thing to remember, unless you are that particular person’s doctor you should NEVER give a diagnosis nor disagree with a diagnosis.

  • pd

    I prefer a lifestyle program vs taking a pill. I think too many of us thinks if we take a pill we don’t need to change our lifestyle to help control a disease. I think a lifestyle program should be strongly recommended by any physician over another pill.

  • upendra

    hi, i am 39 year old, my fasting blood sugar 116mg/dL and PP 171 mg/dl my doctor suggested me take metformin 1000mg. yesterday night i took this tablet but i am still confused should i take tablet or go for diet and exercise. can i stop medication however i have taken one dose.

    • Lil25

      Dont stop taking medicine without talking to your doctor. A lifestyle that embraces good nutrition and plenty of exercise is good for everyone, so why not try it! Reducing sugar and processed foods is also benneficial for nearly everyone, regardless of whether or not they have diabetes. If you want to go low-carb, you don’t really need a prescribed plan to do so; there are dozens of low-carb diets out there. HOWEVER, everyone needs SOME carbs. It would be wise to discuss your diet with a doctor or registered dietician. It would also be very helpful to monitor your blood sugar after meals to see how different types of foods affect you. Not all carbs affect people the same way. Potatoes, for example, are horrible for many T2 diabetics, but they do not seem to affect some others at all.

  • Doug Murray

    Don’t split extended release pill. It causes the medication to drop your blood sugar too fast, followed by insufficient lowering for hours. Just swallow the prescribed pill, as is.

  • Lil25

    Doctors don’t want to treat obese people who are prediabetic because they blame the patient. While the patient’s weight may have contributed to the development of T2D, the causes of both diabetes and obesity are complex. Yet, even doctors are cognitively lazy and choose simply to blame the patient rather than helping them most of the time.