5 Signs Metformin Is Working For Weight Loss – Supporting Your Weight Loss Journey In 2024

Paige Anderson, CRDH
Dr. Maya Frankfurt, PhD
Metformin may make it easier to lose weight and keep it off. Here are 5 signs metformin is working for weight loss.
signs metformin is working for weight loss
Metformin could support your weight loss efforts. Photo: Le Ho

Metformin is one of the most commonly prescribed diabetes medications. It can help decrease high blood sugar and increase insulin sensitivity. Also, as a part of a plan that includes healthy lifestyle changes, metformin may also support weight loss efforts.

It’s important to understand that metformin[1] is not a weight loss drug, although it is commonly prescribed for off-label use to help people lose weight. Off-label use refers to recommendations that have not been approved by the FDA.

In non-diabetic patients, metformin can help support weight loss efforts including diet and lifestyle changes. Although more research is needed, experts believe[2] metformin reduces weight by boosting your glucose metabolism, suppressing appetite, and improving insulin sensitivity.

So, what are the signs that metformin is working for weight loss?

5 Signs That Metformin Is Helping You Lose Weight

  1. Your appetite feels more manageable.
  2. Food feels more satisfying.
  3. You no longer have excessive thirst and urination.
  4. It gets easier to lose belly fat.
  5. You have an overall better sense of wellbeing.

Signs Metformin Is Working For Weight Loss

signs metformin is working for weight loss
Losing weight may be easier with metformin Photo: lithian/Shutterstock

Metformin’s main purpose is blood sugar control for people with type 2 diabetes. However, like other diabetes medications, weight loss is often a side effect of metformin treatment. Therefore in recent years, many people have worked with their healthcare provider to speed up weight loss by incorporating metformin.

Most studies point to only modest weight loss improvement with metformin, but your healthcare provider may suggest incorporating it into a comprehensive approach to reaching and maintaining a healthy weight.

Here are some signs that metformin is working to help decrease your body weight.

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Your Appetite Feels More Manageable

Metformin reduces leptin in the body.[3] Leptin affects appetite by making you feel hungry. By moderating hormones that affect appetite, metformin may make it easier to maintain healthy eating habits and resist previously problematic eating habits.

While it is intended for blood sugar management, continuing to eat excessive sugars and processed foods will interfere with metformin’s ability to control blood sugar and otherwise support your weight loss goals. It is vital to moderate your food intake and eat a healthy diet while taking metformin to see the best outcomes. (Bonus points for incorporating foods that help lower blood sugar naturally!)

Food Feels More Satisfying And Energy Feels More Stable

Metformin can cause a shift in your gut microbiome. Specifically, it increases bacteria[4] that help in the processing of short-chain fatty acids. In turn, short-chain fatty acids regulate your appetite[5] and keep your energy levels stable.

That means your food may feel more satisfying for longer and you may feel less of those energy crashes from fluctuations in your blood glucose, both of which have significant benefits for weight loss in the short and long term.

Decreased Thirst And More Time Between Bathroom Trips

Excessive thirst and frequent urination are hallmark signs of hyperglycemia (high blood sugar levels). People with chronically high blood sugars are more likely to have a body mass index greater than recommended by their healthcare provider. Conversely, high body weight is also a risk factor[6] for chronically high blood glucose.

As metformin works to lower blood sugar, it can help resolve the symptoms of hyperglycemia including excessive thirst and urination, which is a sign that your blood glucose levels are returning to normal and your body will have an easier time losing weight.

It Gets Easier To Lose Belly Fat

Insulin resistance can be a major component of weight gain in nondiabetic people, and may lead to prediabetes and diabetes if left untreated. Insulin resistance is also closely linked[7] with high visceral fat (belly fat).

While the exact mechanism is still being studied,[8] one of the effects of metformin is a marked reduction in belly fat. Researchers think that, independent of appetite suppression, metformin may change the way your body uses energy and help burn visceral fat more efficiently.

You Have An Overall Sense Of Better Wellbeing

Many people struggle with energy highs and lows because of major shifts in their blood glucose levels throughout the day. Because metformin can improve insulin sensitivity, it can help stabilize blood sugar levels, which decreases stress on your body and helps you feel better in general.

Along with the lifestyle changes that will help you lose weight such as  starting each day with a healthy breakfast and getting more exercise, you may be surprised at the change in your mood and overall sense of wellbeing.

How Does Metformin Work To Help With Weight Loss?

signs metformin is working for weight loss
Metformin should only be taken under the guidance of a healthcare professional. Photo: ViDI Studio/Shutterstock

Metformin does a lot in the body.[9] It primarily targets tissues of the liver and gut, where it can lead to changes in gut flora, which may boost its effects on blood sugar and appetite.

It also modulates the immune system and inflammatory markers in the body, which are associated with obesity, and enhances the expression of biomarkers that may facilitate weight loss.

Its effect on weight loss is mostly indirect, and metformin shouldn’t be considered a weight loss medication.

However, it is especially effective[10] in reducing antipsychotic-induced weight gain. Antipsychotic medications are commonly used to treat schizophrenia and psychosis as well as bipolar disorder and depression. 

While antipsychotic medications can be an important component of treating these potentially debilitating conditions, they can cause significant weight gain[11] that can lead to other health problems, lower quality of life, and make people not want to stick with taking their medications as recommended.

If you’re struggling with weight gain from other medications, talk to your doctor about whether adding metformin may be a good strategy for you. 

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Can People Without Diabetes Take Metformin?

In general, metformin is considered safe for most people. It’s not uncommon for physicians to recommend metformin as a weight management aid even though the FDA has not approved metformin as a weight loss medication. 

There are other medications and fat burner supplements available that are targeted at weight loss, but if your healthcare provider thinks insulin resistance may be part of the challenge you face in trying to lose weight, metformin or other diabetes medications may be a better choice, even if you don’t have diabetes.

Most of the research on metformin as a weight loss aid have focused on obese patients and those who have insulin resistance challenges. In patients who have normal insulin sensitivity, there have been mixed findings[12] as to whether metformin will significantly improve your weight loss efforts.

Always talk to your physician or a registered dietician about your concerns with losing weight and keeping it off.


Metformin isn’t a replacement for a healthy diet and regular exercise. In fact, taking metformin without reducing your intake of high-sugar and high-fat foods may not help correct your blood sugar levels at all, and is very unlikely to cause any weight loss.

Metformin also has some risks. Although it’s generally considered safe, it can cause abdominal discomfort, diarrhea, nausea, and vomiting among other side effects.[13]

Metformin can interact with other medications. Let your healthcare provider know if you’re taking any medications including, but not limited to birth control pills, hormone replacement therapy, insulin, calcium channel blockers, niacin supplements, and medications for asthma and colds.

One of the risks associated with metformin is the potential for lactic acidosis,[14] which can cause muscle cramps, spasms, nausea, vomiting, organ failure and even fatal complications. Excessive alcohol and certain foods may increase this risk for people taking the medication. Talk to your healthcare provider about staying safe while taking metformin.

With the right support, you may be able to enjoy better health and more energy with a healthy diet and regular exercise!

Frequently Asked Questions

How quickly do you see weight loss with metformin?

Metformin won’t significantly speed up weight loss, but it may help your body use energy efficiently, which will support your other weight loss efforts like eating a balanced diet and increasing your physical activity.

Will I lose weight faster if I take more metformin?

There is no established recommended dose for weight loss using metformin. However, taking too much metformin can cause dangerous side effects including low blood pressure, lactic acidosis, dangerously low blood sugar, acute renal failure, coma, and cardiac arrest.

How many kgs can you lose on metformin?

Metformin is most effective at preventing and correcting weight gain related to taking antipsychotic medications. In general, metformin is more effective in inducing weight loss in insulin resistant patients.

What happens if I take metformin while fasting?

Studies show[15] that metformin increases fasting glucose clearance, which can improve weight loss. In general, it is considered safe to continue taking metformin during short-term fasting, but it’s always best to consult your doctor for guidance.

What should I avoid while taking metformin?

You should avoid excessive alcohol while taking metformin. Grapefruit, high-sodium foods, and too much fiber may interfere with metformin’s efficacy. High-fat, high-sugar foods can undercut metformin’s effectiveness in controlling your blood sugar and undo your efforts to lose weight.

Can metformin make you sleepy?

Prolonged metformin use may cause vitamin B12 deficiency[16] which can cause fatigue. Feeling weak, dizzy, or fatigued may indicate low blood sugar. Talk to your doctor if metformin makes you feel sleepy to rule out other issues.


  1. Armen Yerevanian and Soukas, A.A. (2019). Metformin: Mechanisms in Human Obesity and Weight Loss. Current obesity reports, [online] 8(2), pp.156–164. doi:https://doi.org/10.1007/s13679-019-00335-3.
  2. Khanyisani Ziqubu, Mazibuko-Mbeje, S.E., Sinenhlanhla X. H. Mthembu, Mabhida, S.E., Jack, B., Nyambuya, T.M., Nkambule, B.B., Basson, A.K., Tiano, L. and Dludla, P.V. (2023). Anti-Obesity Effects of Metformin: A Scoping Review Evaluating the Feasibility of Brown Adipose Tissue as a Therapeutic Target. International Journal of Molecular Sciences, [online] 24(3), pp.2227–2227. doi:https://doi.org/10.3390/ijms24032227.
  3. Armen Yerevanian and Soukas, A.A. (2019). Metformin: Mechanisms in Human Obesity and Weight Loss. Current obesity reports, [online] 8(2), pp.156–164. doi:https://doi.org/10.1007/s13679-019-00335-3.
  4. Mueller, N.T., Zhang, M., Maruthur, N.M., Juraschek, S.P., Miller, E.R., Appel, L.J. and Hsin Chieh Yeh (2021). Metformin Affects Gut Microbiome Composition and Function and Circulating Short-Chain Fatty Acids: A Randomized Trial. Diabetes Care, [online] 44(7), pp.1462–1471. doi:https://doi.org/10.2337/dc20-2257.
  5. Byrne, C., Chambers, E.S., Morrison, D.J. and Frost, G. (2015). The role of short chain fatty acids in appetite regulation and energy homeostasis. International Journal of Obesity, [online] 39(9), pp.1331–1338. doi:https://doi.org/10.1038/ijo.2015.84.
  6. Mouri, Mi. and Madhu Badireddy (2023). Hyperglycemia. [online] Nih.gov. Available at: https://www.ncbi.nlm.nih.gov/books/NBK430900/#:~:text=Major%20Risk%20Factors,desired%20body%20weight.
  7. Yohannes Tsegyie Wondmkun (2020). Obesity, Insulin Resistance, and Type 2 Diabetes: Associations and Therapeutic Implications. Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy, [online] Volume 13, pp.3611–3616. doi:https://doi.org/10.2147/dmso.s275898.
  8. Ichiro Tokubuchi, Tajiri, Y., Iwata, S., Hara, K., Wada, N., Toshihiko Hashinaga, Nakayama, H., Hiroharu Mifune and Yamada, K. (2017). Beneficial effects of metformin on energy metabolism and visceral fat volume through a possible mechanism of fatty acid oxidation in human subjects and rats. PLOS ONE, [online] 12(2), pp.e0171293–e0171293. doi:https://doi.org/10.1371/journal.pone.0171293.
  9. Foretz, M., Guigas, B. and Benoı̂t Viollet (2023). Metformin: update on mechanisms of action and repurposing potential. Nature Reviews Endocrinology. [online] doi:https://doi.org/10.1038/s41574-023-00833-4.
  10. Hakami, A.Y., Razaz Felemban, Rami Ghazi Ahmad, Al-Samadani, A.H., Salamatullah, H.K., Baljoon, J.M., Alghamdi, L.J., Mostafa and Mohamed Eldigire Ahmed (2022). The Association Between Antipsychotics and Weight Gain and the Potential Role of Metformin Concomitant Use: A Retrospective Cohort Study. Frontiers in Psychiatry, [online] 13. doi:https://doi.org/10.3389/fpsyt.2022.914165.
  11. Madhubhashinee Dayabandara, Raveen Hanwella, S.S. Ratnatunga, Sumudu Nimali Seneviratne, Chathurie Suraweera and Varuni de Silva (2017). Antipsychotic-associated weight gain: management strategies and impact on treatment adherence. Neuropsychiatric Disease and Treatment, [online] Volume 13, pp.2231–2241. doi:https://doi.org/10.2147/ndt.s113099.
  12. C. Seifarth, B Schehler and Schneider Hj (2012). Effectiveness of Metformin on Weight Loss in Non-Diabetic Individuals with Obesity. Experimental and Clinical Endocrinology & Diabetes, [online] 121(01), pp.27–31. doi:https://doi.org/10.1055/s-0032-1327734.
  13. Nih.gov. (2020). Metformin. [online] Available at: https://www.ncbi.nlm.nih.gov/books/NBK548726/#:~:text=Metformin%20is%20generally,and%20hypersensitivity%20reactions.
  14. Mahmood, R., Maccourtney, D., Vashi, M. and Ayman Saber Mohamed (2023). A Case of Metformin-Associated Lactic Acidosis. Cureus. [online] doi:https://doi.org/10.7759/cureus.38222.
  15. McCreight, L., Mari, A., Coppin, L., Jackson, N., A. Margot Umpleby and Pearson, E.R. (2019). Metformin increases fasting glucose clearance and endogenous glucose production in non-diabetic individuals. Diabetologia, [online] 63(2), pp.444–447. doi:https://doi.org/10.1007/s00125-019-05042-1.
  16. NHS Choices (2023). Side effects of metformin. [online] Available at: https://www.nhs.uk/medicines/metformin/side-effects-of-metformin/.

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