Is Metformin Used For Weight Loss? What You Need To Know

Forbes

27-06-2025

Metformin is a first-line treatment for type 2 diabetes, approved by the U.S. Food and Drug Administration (FDA) to treat the condition in 1994. While not FDA-approved for weight management, metformin may play a valuable role when used in conjunction with other medications for individuals who have obesity. However, the potential for weight loss as a side effect of metformin use alone remains unclear.
Discover how metformin works and all that it treats, as well as its potential impact on weight loss, other side effects and safety.
'Metformin is a widely used, first-line medication for treating type 2 diabetes . It belongs to a class of drugs called biguanides,' says Hans J. Schmidt, M.D., chief of bariatric surgery and director of the Center for Weight Loss and Metabolic Health at Hackensack University Medical Center in New Jersey. It can be used alongside other medications, such as insulin, or on its own.
'It's typically recommended alongside lifestyle changes like diet and exercise, and is often the first medication doctors turn to because of its strong track record for safety, effectiveness and metabolic benefits,' adds Sam Setareh, M.D ., director of clinical cardiology at Beverly Hills Cardiovascular, attending cardiologist at Cedars Sinai Medical Center and Forbes Health Advisory Board member.
Metformin can be taken via mouth in the form of a tablet, extended-release tablet or liquid. The regular tablet is taken two to three times a day with meals, while the long-lasting, extended-release tablet is taken once daily in the evening with a meal. The liquid solution can be taken once or twice daily with meals. How Does Metformin Work?
'It works primarily by reducing glucose production in the liver. This is a major contributor to high blood sugar in people with type 2 diabetes,' explains Dr. Schmidt. Metformin helps to manage the amount of glucose in the blood, reducing how much glucose is absorbed from food and produced by the liver. 'Additionally, metformin improves insulin sensitivity, which helps the body's cells use insulin more effectively to absorb glucose from the bloodstream,' he adds.
'Unlike some diabetes drugs, it doesn't force the pancreas to produce more insulin, which means it carries a low risk of causing low blood sugar,' notes Dr. Setareh.
'Metformin is primarily used to treat type 2 diabetes. It helps manage blood sugar levels by reducing glucose production in the liver, improving insulin sensitivity, and slightly decreasing glucose absorption in the intestines,' says Dr. Schmidt. Note that this drug manages type 2 diabetes and does not cure it. Metformin should not be used to treat type 1 diabetes.
'I cannot stress enough that metformin is not a primary weight loss medication,' adds Dr. Schmidt. 'It's used to treat certain conditions that are associated with increased weight, like insulin resistance and polycystic ovary syndrome (PCOS). Patients may lose weight as their underlying condition improves. But it is not for the general population.' Does Metformin Help With Weight Loss?
Metformin is primarily a diabetes medication and not typically a first-line treatment for weight loss or prescribed solely for weight loss, according to Dr. Schmidt. 'Metformin can contribute to modest weight loss or help prevent weight gain, but it's not primarily a weight loss drug. While some people experience noticeable weight loss, others maintain their weight or even experience a slight weight gain,' he adds.
Metformin's effect on weight isn't yet fully understood, but it's thought to be related to decreased appetite, reduced glucose absorption in the gut and changes in how the body stores and uses fat, explains Dr. Schmidt. He adds that the impact on weight can largely vary, with some people noticing weight loss and others experiencing no change at all. 'The weight loss associated with metformin tends to plateau after a year or so. It's not a quick fix or a long-term solution for significant weight loss,' he says.
Metformin is most effective for weight management when used in conjunction with regular exercise and a healthy diet, says Dr. Schmidt. 'These lifestyle changes are crucial for achieving and maintaining a healthy weight.'
Ozempic is a brand-name form of semaglutide , a glucagon-like peptide-1 (GLP-1) receptor agonist. While Ozempic is FDA-approved to treat type 2 diabetes and reduce the risk of certain medical conditions or events, neither Ozempic nor metformin is FDA-approved for weight loss .
The two medications do have similarities: Both are prescription medications that can be used in the treatment of type 2 diabetes, help to reduce blood sugar levels and can be taken alongside additional diabetes medications, such as insulin, for better blood sugar control, according to Dr. Schmidt.
Both drugs have also shown benefits outside of blood sugar management. Metformin may have a positive impact on PCOS, with many studies showing it could be potentially useful in treating PCOS-related infertility.
However, when treating type 2 diabetes and lowering blood sugar, the two medications work through different mechanisms with differing characteristics. Metformin works by reducing glucose production in the liver and improving insulin sensitivity, whereas Ozempic mimics a natural hormone called GLP-1 , which increases insulin release when a person's blood sugar is high, suppresses glucagon secretion, slows stomach emptying and promotes a feeling of being full, according to Dr. Schmidt.
In January 2025, Ozempic was FDA-approved to reduce the risk of major cardiovascular events, such as stroke, in individuals with type 2 diabetes and known heart disease, as well as lower the risk of kidney failure, kidney disease worsening and death as a result of cardiovascular disease in those with type 2 diabetes and chronic kidney disease. While weight loss may also be a common side effect of using Ozempic, it is not FDA-approved for weight management.
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'Metformin is generally well-tolerated, but some people experience side effects, most commonly gastrointestinal issues,' says Dr. Schmidt. While these can improve over time or with dose adjustments, he notes the following to be potential side effects: Nausea
Stomach pain
Vomiting
Indigestion
Diarrhea
Metallic taste in the mouth
Loss of appetite
'Some people notice a metallic taste, and over long periods, metformin can lower vitamin B12 levels, which may lead to fatigue, numbness or other symptoms if not monitored,' explains Dr. Setareh. 'In rare cases, particularly in people with kidney or liver problems, there's a risk of lactic acidosis, a serious but uncommon complication. Metformin generally doesn't cause low blood sugar unless it's combined with other medications that do.'
'It's also crucial to remember that Metformin is a prescription medication and should only be used under the guidance of a healthcare professional. Never self-medicate,' adds Dr. Schmidt.
It's best to speak to your doctor before taking metformin to discuss all potential risks and side effects. Is Metformin Safe?
'Metformin is generally considered a safe medication when prescribed and monitored appropriately. It has a long history of use and a well-established safety profile. However, like all medications, speak to your doctor before taking it,' notes Dr. Schmidt.
Anyone taking the drug should follow their prescription label carefully and take the drug exactly as directed by their physician. Individuals should continue taking the drug even if they feel well.
If you're thinking about metformin for weight management, it's essential to discuss this with your doctor, who can assess your situation, determine if it's appropriate and discuss your potential risks and benefits, advises Dr. Schmidt. More effective weight loss medications are available for your consideration, if weight loss is your primary goal.
'All in all, metformin remains a reliable option for managing blood sugar and may offer some additional metabolic benefits. It may help with some weight loss, but it's no magic pill; it works best when paired with healthy lifestyle changes,' adds Dr. Setareh.