Doctors typically prescribe metformin for people with diabetes or prediabetes to help manage the condition. People who take the medication may experience weight loss.

Recall of metformin extended release

In May 2020, the Food and Drug Administration (FDA) recommended that some makers of metformin extended release remove some of their tablets from the U.S. market. This is because an unacceptable level of a probable carcinogen (cancer-causing agent) was found in some extended-release metformin tablets.

If you currently take this drug, call your healthcare professional. They’ll advise whether you should continue to take your medication or if you need a new prescription.

Metformin is a drug for managing blood sugar levels in people with type 2 diabetes. You may have heard that metformin can also help you lose weight. But is it true?

Here’s what you should know about what metformin can do for weight loss, as well as why a doctor or healthcare professional may prescribe it for you.

The FDA doesn’t approve metformin as a stand-alone weight loss drug.

However, people using metformin for other means may lose weight as a side effect. The exact mechanism of this is unclear. Unlike other diabetes medications, metformin doesn’t cause weight gain.

Appetite reduction

One theory is that metformin prompts you to eat less by reducing your appetite. However, the methods by which metformin affects appetite aren’t clear.

Metformin may interfere with the gut microbiota, prompt the release of appetite-suppressing hormones, and affect appetite-regulating parts of the brain.

Some people who take metformin may also experience diarrhea, bloating, and nausea. These side effects may reduce how much a person wishes to eat.

Long-term weight loss

One long-term study of people with diabetes assessed weight loss over 15 years. Researchers found that in people who lost more than 5% of body weight in the first year, those taking metformin had greater success with maintaining weight loss in years 6 to 15.

However, taking the drug without following other healthy habits may not lead to weight loss. Individuals who follow a healthy diet and exercise while taking metformin tend to lose the most weight.

In addition, any weight loss you have may only last as long as you take the medication. That means if you stop taking metformin, there’s a good chance you’ll return to your original weight. And even while taking the drug, you may slowly gain back any weight you’ve lost.

If you have type 2 diabetes or prediabetes and are overweight or have obesity, a doctor may prescribe metformin to help you manage your diabetes or lower your risk of developing it.

In fact, a doctor might prescribe metformin for weight loss even if you don’t have diabetes or prediabetes. This is an off-label use.

Off label means that the FDA hasn’t approved a drug for a specific use, which in this instance is as a weight loss aid. As a result, there’s less information about how effective it is for this purpose.

Metformin is a diabetes medication. There are no official dose recommendations for it as a weight loss aid.

If a doctor prescribes metformin for you off label, they’ll decide on a dose that’s right for you and your medical circumstances. You’ll likely start metformin at a low dose and gradually increase it over a few weeks. This can help minimize any side effects.

One off-label use of metformin is for antipsychotic drug-induced weight loss. Doses for immediate-release metformin can range from 750 mg to 2,000 mg. Extended-release doses may range from 500 mg to 2,000 mg.

If you’re losing weight while taking metformin, it may or may not be the result of the medication. Weight loss can result from other factors as well.

Digestive issues

Digestive system issues may also cause weight loss. These issues include:

Other health conditions

Some health conditions may also cause loss of appetite, which can lead to weight loss. These conditions include:


Other medications may also cause weight loss. For example, chemotherapy drugs may do this by reducing your appetite.

Certain thyroid medications boost your metabolism, which can cause weight loss. One symptom of an underactive thyroid is weight gain. Taking medications to treat this may cause weight loss as hormones rebalance. These drugs include levothyroxine, liothyronine, and liotrix.

Other drugs that may cause weight loss as a side effect include some attention deficit hyperactivity disorder drugs, such as amphetamine/dextroamphetamine (Adderall) and methylphenidate (Concerta).

Learn more about Adderall and weight loss here.

Keep in mind that metformin is a relatively safe drug with side effects that usually go away over time. Any weight loss you may have while taking it should be gradual and minimal and not cause alarm.

If you’re concerned about the amount of weight you’ve lost while taking metformin, talk with a doctor. They can help determine what’s causing your weight loss.

Whether or not you take metformin, you should call a doctor if you’re losing weight rapidly and have no energy or appetite. In general, you should feel free to call any time you have questions or concerns about your health or your weight.

Learn why you may experience unexplained weight loss here.

The road to weight loss varies from person to person. Still, the weight loss method doctors typically recommend is a combination of a balanced diet and exercise. For more information, read about diabetes-safe diets and exercise tips for people with diabetes.

Talk with a doctor to learn more about metformin and weight loss. They can answer your questions and help you find a weight loss plan that’s right for you. Some questions you might ask include:

  • Can you recommend a diet and exercise program to help me lose weight?
  • Do I need medication to help me lose weight?
  • What’s a reasonable weight loss goal for me?
  • Should I work with a dietitian to help with my diet?
  • If I lose weight, could I stop taking some medications for diabetes, high cholesterol, or high blood pressure?