Metformin May Not Help Overweight Adolescents With Type 1 Diabetes

Metformin is the most widely prescribed diabetes medicine in the world, with more than 61 million prescriptions filled in 2012 in the United States alone. But according to a recent study, the drug may not improve blood sugar levels in overweight teens with Type 1 diabetes.


Metformin works by decreasing the amount of glucose made by the liver and by improving insulin sensitivity in the liver, muscle, and fat cells. To assess how safe and effective the medicine is in overweight adolescents with Type 1, researchers from the Jaeb Center for Health Research randomly assigned 140 youth ages 12 to 19 who’d had diabetes for an average of seven years to take either metformin (2,000 milligrams a day or less) or placebo (inactive treatment) along with their insulin for six months.

Although there was a small benefit on HbA1c (a measure of blood sugar control over 2–3 months) early on in those taking metformin, the researchers found that this benefit disappeared by the study’s end, with participants in both groups ultimately experiencing an HbA1c increase of approximately 0.2%. The researchers suggest that it seems unlikely that different results would have been achieved with a longer treatment period. Additionally, metformin did not improve various heart health markers, such as blood pressure and cholesterol levels, and it was associated with increased gastrointestinal issues compared to placebo.

“These results do not support prescribing metformin to adolescents to improve glycemic control,” according to the researchers.

However, according to endocrinologist Spyros Mezitis, MD, PhD, who was not involved with the study, the medicine did offer the youth some benefits, including decreasing the amount of insulin they used and being associated with weight loss. Metformin also reduces insulin resistance and appetite and lessens glucose production by the liver, he notes, suggesting that more trials are necessary to evaluate the effects of the drug in overweight adolescents with Type 1 diabetes before prescribing practices are changed.

For more information, read the article “Metformin May Not Help Obese Teens With Type 1 Diabetes” or see the study abstract in The Journal of the American Medical Association. And for more information about metformin, see the article “Metformin: The Unauthorized Biography,” by diabetes educator Wil Dubois.

Low blood glucose is one of the most feared consequences of diabetes treatment in people who use certain diabetes medicines. Bookmark and tune in tomorrow to learn how to determine if you’ve been experiencing hypoglycemia and how it can be avoided in our new presentation from the AADE’s 2014 Educator of the Year, Gary Scheiner!

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  • Mary

    HI I was told I have Type 2 Diabetes and that was 5 1/2 years ago. My Doctor gave me Metformin from the very start and it’s working very well for me. Yes there are some people who can’t take it but there are some like me who can. So it shouldn’t be downdraged to say it doesn’t work at all. It’s just it doesn’t work for everyone. And that’s because everyone who has Diabetes it’s different no 2 people’s Diabetes is the same which is why some people have some problems with theirs when other people don’t. So for those of you millions of people who can’t take Metformin there is some kind of Diabetic Medicene you will be able to take that will work for you. Good Luck and God bless all the Diabetes in the world.

    • Margareth Santos

      Metformin did work fantastically well for me, it did lower my blood sugar and A1C and help on my weight los.I am not just relay on medication to do all the job, I eaten right and smoll pocion and exercise a lot.

  • Ronna Blackley

    It seems to work for me, although I have made diet changes. I cut out all sugar, unless it is naturally found in fruit. I don’t eat processed foods, and avoid high fructose corn syrup. I am living as though I want to live a long and healthy life, I am not depending on the medication to “do” it for me, by continuing to fill it with junk. I have lost over 30lbs, which made my a1c go from 6.5 to 5.5 at last check. I am prescribed to take it twice per day, but I usually only take the morning dose, as I forget the evening one.

  • Lamont DozierSr

    My doctor has me taking 1000mg Metformin but my sugar levels are still high?? Your advice on what I should do???

    • Lue55

      Ask your Doctor to let you try Glipizide 5mg twice a day before breakfast and dinner. This works for me.

  • monnim

    metformin put me into kidney failure after one week of taking it

  • Lue55

    I have been taking metformin for over five years and it has been okay. My sugar level has been high in the morning until my Doctor added another medication called Glipizide 5MG. I take one half tablet by mouth two time a day before breakfast and supper. Now my sugar in the morning is between 95-105. Other than this metformin has been okay.
    I am taking 1000 units of metformin twice a day, morning and at bed time.

  • donstanton

    I am one of those that cannot take Metformin. I was diagnosed in 2006 and started with Lantus injections once per day. I was able to keep my blood sugar between 80 & 100 with an A1c of 5.7. After 2-1/2 years my doctor decided to put me on pills. He put me on a 500 mg dose of Metformin and my blood sugar went up to 125 low and 180 high, my A1c increased to 6.5. So my doctor increase the dosage to 750 mg once daily and told me to keep my sugar between 150 & 200, and my blood sugar went higher and my A1c increased to 7.1, so my doctor increased the dosage to 1000 mg daily and told me to keep my sugar below 250, and I it was a struggle to keep my sugar below 250. Before taking the Metformin I had one or two symptoms that I was diabetic. Taking the Metformin I had 28 symptoms of diabetes. I researched side effects and allergies of Metformin and discovered that I had all the allergy symptoms. When my doctor took me off of Metformin my A1c had increased to 8.6. I have been taking Lantus Solor star for a little over a year, my blood sugar on average is 100 to 117 and my A1c is down to 7.1.

    • JohnC

      So when are you going to get a new doctor who actually knows what they’re doing. Insulin can be a very good thing if used properly.

  • Steve from New York City

    I’m a type II diabetic being treated as a type I
    Early in my treatment program, I was given Metformin as one of my oral regimens, and it worked well with diet for a while. Then, without warning and without a contributing factor (such as a cold or an illness), it simply stopped working!
    The numbers became severely high and insulin was given to bridge the gap.
    Now, I’ve migrated to long- and short-acting insulin, which kept my numbers in check but made my weight go up!!
    What I discovered was that, by removing the foods that trigger my spikes in glucose, and the resulting need for larger doses of insulin, I’ve been able to much better control my A1C range, my general control and my weight (slowly dropping and now down 40 lbs.). These turned out to be ALL starches, almost ALL sugars (my liver makes enough, thank you) and the vast majority of grains. I also found out that milk had more sugar per ounce than sweetened soda – who knew? It’s basically a Paleo diet, with hard dairy included (hard cheeses with little or no carbs). It’s so difficult to maintain for me, since my brain keeps sending out for sandwiches, but I am getting used to it.
    My cholesterol is REALLY good even with the increase in fat intake, since I discovered that my serum cholesterol is NOT related to my intake of cholesterol! Sadly, my (former) dietitian was old-school.
    It is, and will always be, a balancing act, but it’s no longer a constant struggle.

  • candlevixen

    I’m not really controlled on MEtformin and Glipizide. My levels are constantly high, regardless of what I eat, what I do to work out, and how I take the meds.

    I’m frustrated. I know I need to eat better and work out more, but still….I’m feeling burnout. Does anyone have suggestions for combating that?

  • Janna

    Though the Metformin did reduce my levels a good bit, I found the side effects of diarrhea worse than the cure in this case..I had severe diarrhea with this medication. And sometimes it was difficult to work due to having ‘accidents’ and needing to carry clothes to work with me or when just out and about in general…I have also heard other users complain of the same thing..I also have a liver disorder called hemochromoatosis – in which my body stores too much iron…and my body is insulin resistant…therefore, Metformin was not a good choice…it was great with weight loss and controlling the sugar; however, I had to choose to discontinue it for my own sake..others have mentioned problems with diarrhea while taking this medication..

  • CD

    I was diagnosed about 5 years ago with type 2. I was on Metformin for 3 weeks and my blood sugars didn’t improve. Suddenly I got very ill. After an hour of uncontrolled vomiting just fluids, I was taken to the ER. Severely dehydrated an exhibiting the signs of diabetic ketoacidosis, I was admitted to ICU where I remained for 3 days until my levels could be stabilized. As a result of that experience I was told to go onto insulin 4 times a day and re-diagnosed as type 1. Apparently, I was type 1 from the beginning, when the DKA kicked in it proved that I was “insulin dependent”. Although I liked not having to inject myself several times a day, it makes you think about what you eat because you have to test so often to adjust the insulin dose. Which is not really a “bad thing”!

  • Ralph

    I was prescribed Metformin 500mg. about 4 years ago for type 2 Diabetes. The initial effect was severe gastointestinal upset. At the end of three months, my blood glucose and A1c were up so the Dr. upped the dose to 750mg per day. Another three months and A1c was up, so the dose was up to 1000mg per day. The gastrointestinal upset worsened. Three months and again A1c was up, so the dose was upped to 1500mg per day.. Another three months and the dose was upped to 2250 mg. per day. At that time my ALT and AST(liver enzymes) results were elevated. The gastrointestinal upset was becoming intolerable. At that point, I had to go in the hospital for another situation. I was taken off all meds. My AST and ALT went back to normal and my glucose immediately lowered. After the hospital stay I was permanently taken off Metformin and my gastrointestinal upset disappeared. I am still Diabetis; but, the new medications are working better than the Metformin, without the severe gastrointestinal upset.

  • Asbrown

    ARRRGH! The online drug information about metformin says it is “ineffective below 2000 mg/day” and yet you cannot get anyone to prescribe that dose! This study says “2000 or less” why would they think its going to work?