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!

  • 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.

  • 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.

  • 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.