Does Metformin Help You Lose Weight?
Last updated October 27, 2026
Short answer: Metformin is approved for type 2 diabetes, not for weight loss, and the weight loss it produces is modest. In the Diabetes Prevention Program, adults at high risk of diabetes who took metformin lost an average of 2.1 kg (about 4.6 pounds), compared with 0.1 kg on placebo and 5.6 kg in the lifestyle program. Approved weight loss medicines averaged far more in their own trials.
What metformin is approved for
The metformin label describes it as an adjunct to diet and exercise to improve blood sugar control in adults and children 10 and older with type 2 diabetes. Weight loss is not an approved use, so taking it for weight loss is an off-label decision for a prescriber to make.
What the best study found
The Diabetes Prevention Program randomly assigned 3,234 adults without diabetes but at high risk to placebo, metformin or a lifestyle program aiming for at least 7% weight loss and 150 minutes of activity a week.
| Group | Average weight loss | Diabetes risk vs. placebo |
|---|---|---|
| Placebo | 0.1 kg | Baseline |
| Metformin | 2.1 kg (about 4.6 lbs) | 31% lower |
| Lifestyle program | 5.6 kg (about 12 lbs) | 58% lower |
In longer follow-up, the NIDDK reports that metformin delayed diabetes by 18% at both 10 and 15 years.
How that compares with weight loss medications
In the trials behind their labels, Wegovy averaged 14.9% weight loss and Zepbound up to 20.9%, in people with obesity or overweight and without diabetes. The metformin average in the Diabetes Prevention Program was a few pounds. These were different studies in different people, but the gap is large. See weight loss medications compared.
If you take metformin and are not losing weight
- That is common given the modest average effect in the study above.
- Do not change or stop metformin on your own. It is prescribed for blood sugar control.
- Ask your prescriber whether a medicine approved for weight management is appropriate. See the BMI guide for what the labels say.
- If you have prediabetes or insulin resistance, lifestyle change had the strongest results in the Diabetes Prevention Program. See our guide on that.
Related: losing weight with insulin resistance, lifestyle vs. GLP-1 weight loss and BMI requirements.
Sources
See what a weight-management medication could mean for your own numbers.
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This calculator is for educational and informational purposes only and does not provide medical advice, diagnose any condition, recommend or prescribe treatment, or guarantee results. Estimates are based on information you provide and published clinical-trial averages. Individual results can vary significantly.
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