A promising future
As of today, metformin is FDA-approved only for use in type 2 diabetes as a blood-glucose-lowering agent. However, it is increasingly used off-label by people with type 1 diabetes to reduce insulin requirements, which it most likely achieves through its insulin-sensitizing effects. Some doctors also prescribe it to people with type 1 diabetes who are overweight, to counteract the weight gain from insulin that some people experience.
Beyond diabetes, metformin is an effective treatment for polycystic ovary syndrome (PCOS), for which it can increase ovulation rates fourfold. While it is not FDA-approved for this use, metformin features prominently in the treatment guidelines for PCOS of many organizations worldwide, including the American College of Obstetricians and Gynecologists. In the area of HIV/AIDS treatment, metformin is sometimes used to reduce cardiovascular risk factors. And far on the cutting edge of medical research, metformin is being evaluated for its potential to reduce the growth of tumors.
Closer to its original home, metformin is increasingly used in efforts to prevent type 2 diabetes, or at least to delay the onset of full-blown diabetes in people with prediabetes. Although metformin is not FDA-approved for prediabetes, more and more doctors prescribe it to keep blood glucose levels in the normal range for as long as possible.
After more than 50 years, it is safe to say that metformin is still going strong.