6 benefits of the diabetes medication metformin

Metformin is a medication commonly used to treat people with Type 2 diabetes. It lowers your blood glucose levels, which reduces the risk of diabetic complications such as kidney disease and nerve damage. But since its FDA approval for the treatment of Type 2 diabetes back in 1994, metformin has emerged as something of a “miracle drug” thanks to its effectiveness in treating other common health conditions, like infertility, obesity, and heart disease. 

Though metformin isn’t technically approved for use in treating anything other than diabetes, many healthcare providers prescribe it off-label because of the growing body of evidence supporting these added benefits. Metformin is also being studied for its potential to reduce the risk of certain types of cancer, as well as stroke and dementia. 

Read on to learn about these proven effects and promising future uses of metformin.

6 benefits of metformin

Metformin is an oral antihyperglycemic drug (i.e., a drug that lowers blood glucose) in the class of medications called biguanides. It works primarily by decreasing glucose production by the liver and improving insulin sensitivity, says Shawhin Karimi, MD, an endocrinologist at Houston Methodist Willowbrook Hospital in Houston. This makes the medication a frontline treatment for Type 2 diabetes, but its benefits don’t begin and end there. It is good for assisting with weight loss, improving fertility outcomes, and reducing cardiovascular inflammation—among other things. Read on to find out how and why metformin works to improve health.  

1. Improves diabetes health

Improving the health of people with diabetes is the primary reason providers prescribe metformin. It has many potential benefits for people with diabetes, says Sitembile Sales, MD, internal medicine and integrative medicine physician with Medical Offices of Manhattan in New York. These include:

• Weight loss
• Lower risk of diseases in the large blood vessels of the body, like the brain and heart, and in the small blood vessels of the body, like the eyes, nervous system, and kidneys
• Fewer cardiovascular events and less cardiovascular mortality 
• Better cholesterol levels
• Lower risk of kidney disease and end-stage kidney failure 

It’s important to remember that metformin should be used in conjunction with other interventions; Dr. Sales says lifestyle modifications like smoking cessation, healthy dietary changes, and exercise need to be part of any diabetes treatment plan. Studies show that a combination of metformin and lifestyle changes can have positive impacts on diabetes health.

2. Provides cardiovascular benefits

Metformin decreases your LDL cholesterol levels (the bad kind) and increases your HDL cholesterol levels (the good kind), says Danielle Kelvas, MD, a primary care physician with The HCG Institute in Chattanooga, Tennessee. This is one reason for the cardioprotective benefits of metformin.

There are other reasons, too, says Dr. Karimi; metformin has anti-inflammatory effects, improves functioning in the cells that line the interior of blood vessels, and protects against oxidative stress and damage to the heart muscle. However, Dr. Karimi explains that while these potential cardiovascular benefits are noteworthy, metformin isn’t a primary treatment for cardiovascular diseases, such as heart failure.

3. Aids with weight loss

Metformin is a great drug for weight loss whether or not a person has Type 2 diabetes. “It’s affordable, generic, doesn’t go on shortage, and has a low side effect profile, meaning that most everyone can tolerate it,” Dr. Kelvas explains. 

Even more importantly, you can lose belly fat with the use of metformin (and losing belly fat can lower your risk for heart disease and hypertension, among other chronic health conditions). 

How does metformin work to reduce stubborn belly fat? Dr. Kelvas says the drug decreases the rate of gluconeogenesis—which is the complicated biochemical process by which the body processes, stores, and uses glucose—and this has the effect of helping your body eliminate visceral fat, or excess fat stores in parts of the body like your midsection. 

4. Assists with fertility health

Metformin doesn’t directly impact fertility in the traditional sense, but if you’re experiencing infertility because of polycystic ovarian syndrome (PCOS), metformin can treat many of the common problems that cause fertility issues.

“People with PCOS are at a high risk of developing Type 2 diabetes not just because of weight gain, but because they have a genetic predisposition to developing insulin resistance,” Dr. Kelvas says. “Keeping your blood sugar regulated and keeping your weight down can improve all the symptoms of PCOS, from acne to infertility.”

In other words, metformin helps control the endocrine complications of PCOS that exacerbate infertility. That’s (possibly) not all it does, either: Some studies show that metformin can induce ovulation as well, but currently, using metformin to induce ovulation in women with PCOS is not considered a first-line treatment.

5. Reduces cancer risk

Recent studies suggest metformin may be able to reduce the incidence of pancreatic, liver, breast, and colon cancers in people with diabetes, says Dr. Sales. This research is still emerging; a large 2019 meta-analysis of studies on metformin and cancer showed promise with metformin decreasing pancreatic cancer incidence and improving survival rates for people with colorectal cancer. But that particular analysis did not show a decrease in the incidence of breast, liver, colon, or other types of cancers. 

6. Lowers risk of stroke and dementia

Finally, metformin may be associated with a lower risk of stroke and dementia, though again, the evidence is emerging, and nothing definitive has been shown. The preliminary data is promising, however, thanks to what we know about Type 2 diabetes and brain health: “Blood sugar control helps to reduce the risk of stroke, dementia, and what neurologists are calling ‘Type 3 diabetes,’” says Dr. Kelvas, referring to a type of diabetes associated with Alzheimer’s disease.

If metformin helps maintain healthy blood sugar levels, it follows that the drug may also be able to lower the incidence of stroke and prevent other brain disorders caused by diabetes.

What is metformin approved to treat? 

Currently, the FDA has only approved metformin for the treatment of Type 2 diabetes mellitus. However, there are many off-label uses for metformin, says Dr. Sales, including the treatment of:

• Gestational diabetes 
• Weight gain caused by the use of certain medications, such as antipsychotics
• Polycystic ovarian syndrome (PCOS) and hirsutism (excess hair growth on the body), oligomenorrhea (infrequent menstrual periods), and anovulatory infertility, all of which are associated with PCOS

Metformin may also be used to treat prediabetes or to prevent Type 2 diabetes in certain populations, Dr. Sales says. The people who benefit the most are those who are at high risk of developing Type 2 diabetes, such as people younger than 60, people with a BMI over 35, and women with a history of gestational diabetes.  

Dosages vary based on the patient’s overall health (such as the severity of diabetes and other coexisting medical conditions), but the typical range for an adult is between 500 to 2,000 mg per day.

Metformin side effects 

According to Dr. Sales, the most common side effects of metformin include:

• Gastrointestinal upset, including diarrhea, nausea, vomiting, gas, heartburn, and  stomach pain
• Weakness
• Headache 
• Vitamin B12 deficiency, because metformin may reduce the stomach’s ability to absorb this nutrient

Less commonly, you may experience other side effects such as sweating or low blood sugar (hypoglycemia). Some people get lactic acidosis, which is a dangerous buildup of lactic acid in the blood. It can cause death if not treated, so if you have any of the following symptoms, you should get emergency medical help: muscle pain, feeling cold, difficulty breathing, dizziness or lightheadedness, weakness, vomiting, or slow or irregular heart rate. 

If you’re concerned about side effects, talk to your healthcare provider. Some of these side effects can be mitigated by increasing your dosage very slowly, using extended-release formulations instead of immediate-release formulations, and supplementing with vitamin B12 while taking metformin. 

The bottom line: Talk to your doctor about using metformin

Metformin is a widely used drug in the treatment of Type 2 diabetes, but its potential benefits may extend to many other disorders and conditions, including heart disease, obesity, infertility, cancer, and dementia. In the future, it’s possible that metformin could even be used to treat age-related diseases and increase life-span. The Targeting Aging with Metformin (TAME) trial is one of many studies currently looking into these claims.

But at this point in time, the FDA has only approved metformin for the treatment of diabetes. If you are curious about metformin’s other health benefits, talk to your healthcare provider.

“Using metformin for reasons not approved by the FDA should always be done in consultation with a healthcare provider due to the limited scientific evidence supporting its effectiveness and safety for specific conditions,” Dr. Karimi says. In other words, never take metformin off-label without informing your provider and discussing the pros and cons of off-label use.