Metformin is one of the oldest treatments for type 2 diabetes, known for its ability to help control high blood sugar, but the medication may hold promise for treating a host of additional health conditions as well.
Available at pharmacies across the United States, with a relatively affordable price tag, metformin plays a role in preventing the onset of diabetes in people who are high risk, reducing one’s risk of a number of diabetes complications, treating symptoms and complications of polycystic ovary syndrome (PCOS), and more.
What Is Metformin?
Metformin is a type of medication called a biguanide that lowers blood glucose levels by decreasing the amount of glucose produced by the liver and by promoting insulin-stimulated glucose uptake in muscle and fat. Available in the United States since 1994, metformin is recognized as a first-line medication for treating type 2 diabetes.Metformin is available under the brand names Fortamet, Glucophage, Glumetza, and Riomet. The U.S. Food and Drug Administration (FDA) has only approved metformin for the treatment of type 2 diabetes, although healthcare providers are able to prescribe it for other uses.Susan L. Besser, MD, a primary care physician with Mercy Medical Center in Overlea, Maryland, says that metformin is widely available by prescription and is relatively affordable, with a 90-day supply costing less than $25 via a number of pharmacy retailers. It’s also known to be safe, with typically mild side effects like nausea, stomach upset, and diarrhea, and more severe side effects being only a rare occurrence.
Metformin as a Type 2 Diabetes Treatment
“[Metformin] is mainly a medication for the treatment of diabetes,” says Marcio Griebeler, MD, an endocrinologist at the Cleveland Clinic in Ohio. “Metformin is so popular because it’s inexpensive and can reduce one’s glucose levels and A1C (blood sugar average for three months) the most, compared with other diabetes medications,” he says.
Metformin is generally part of a diabetes maintenance plan, working in conjunction with a diabetes-friendly diet and exercise routine. It’s usually taken once or twice a day with food and can require anywhere from one week to two months to see blood sugar improvements.
Metformin and GLP-1 receptor agonist medications like semaglutide (Ozempic) and tirzepatide (Mounjaro) are often prescribed together to help manage blood sugar levels even more effectively in people with type 2 diabetes. While the two classes of medications provide similar benefits, they work differently, and experts say they work better when taken together.
Preventing Type 2 Diabetes Complications With Metformin
Metformin is primarily prescribed to treat high blood sugar, but it may also provide a number of other benefits to patients with type 2 diabetes, potentially reducing their risk of several other health concerns.
“Several studies show that metformin can decrease the long-term complications of diabetes, including cardiovascular events and cardiovascular mortality, myocardial infarction (heart attack), heart failure, arterial revascularization, stroke, and death,” says Dr. Griebeler.
Heart Problems People with diabetes are twice as likely to have heart disease than people without diabetes. Metformin appears to offer cardioprotective effects to people with type 2 diabetes, potentially hindering the progression of atherosclerosis (plaque buildup) and reducing one’s risk of experiencing an acute heart attack. “Metformin can also improve [one’s] cholesterol profile,” says Griebeler.Stroke People with diabetes are also twice as likely to experience a stroke than people without diabetes. Metformin appears to have a modest impact in reducing this risk in people with type 2 diabetes.Cancer Metformin may help reduce the risk of developing several types of cancer, especially breast and colorectal cancers, in people with diabetes. However, this connection requires further study, as not all available research reports a difference in cancer occurrences in people who take the medication.Dementia There’s also a positive association between metformin use and a reduced risk of dementia in individuals with type 2 diabetes, suggesting that the medication can serve as a complementary therapy alongside first-line treatments for those at higher risk of cognitive decline. Uncontrolled diabetes is linked to an elevated risk of Alzheimer’s disease.
Off-Label Uses of Metformin
Though the FDA has only approved metformin to treat type 2 diabetes, the medication may provide a host of other health benefits for people with or without diabetes. Griebeler says that it’s currently being used off-label to help treat obesity, PCOS and related fertility challenges, and weight gain caused by antipsychotic medications, as well as to prevent diabetes.
Obesity When people who don’t have diabetes but are overweight take metformin, the medication helps with weight loss, says Dr. Besser. “I have used [metformin] for obesity management — for some with normal sugars, some prediabetic — and it helps,” she says. “It’s not a miracle cure, but it does seem to help.” She says to expect only a modest 10 to 15 pounds of weight loss, but she adds that that progress could inspire people to stay on track with their goals. “It’s enough to kick-start things. For anyone who’s quite overweight, any weight loss is encouraging. It makes them want to keep going,” says Besser.
What’s more, people who are overweight or have obesity who also navigate knee osteoarthritis may experience a noticeable reduction in related pain when taking metformin.PCOS Metformin can be a helpful component of a PCOS treatment plan, improving the body’s insulin sensitivity, which can then support overall hormone balance, healthy menstrual cycles, and fertility. And for women with PCOS who become pregnant, there’s some evidence that metformin may lower their risk of early pregnancy loss and preterm birth.
“Diabetes doesn’t cause PCOS, but people with PCOS have a higher risk of developing diabetes,” says Besser. She’s used metformin to treat people with PCOS, including a couple of people who managed to become pregnant after they started taking it.
Medication-Related Weight Gain Metformin also appears to be an effective pharmacological treatment of antipsychotic-induced weight gain, which is commonly experienced among people who take medications for psychiatric diseases like schizophrenia.Diabetes Prevention Alongside healthy lifestyle interventions, metformin can be an effective therapy for reducing higher-risk individuals’ likelihood of developing type 2 diabetes. It appears particularly helpful for people who are overweight or have obesity but don’t have diabetes.Long COVID Metformin may also play a role in treating long COVID, a range of health problems that may persist or develop after a COVID-19 infection. In fact, people who receive early outpatient COVID-19 treatment with metformin may reduce their risk of developing long COVID by as much as 41 percent.
