Is Weight Loss a Side Effect of Metformin?

Table of ContentsView AllTable of ContentsHow Metformin WorksWeight Loss As a Side EffectCould Metformin Be Used for Weight Loss?Can You Take Metformin If You Don’t Have Diabetes?When to See a Healthcare ProviderFrequently Asked Questions

Table of ContentsView All

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Table of Contents

How Metformin Works

Weight Loss As a Side Effect

Could Metformin Be Used for Weight Loss?

Can You Take Metformin If You Don’t Have Diabetes?

When to See a Healthcare Provider

Frequently Asked Questions

Metformin is commonly prescribed for managing blood sugar levels in individuals withtype 2 diabetes.

Some people may experience weight loss as a side effect of taking metformin. There are a few reasons why metformin may contribute to weight loss, including its role in decreasing appetite and changinggut bacteria.Metformin is also known to cause gastrointestinal-related side effects, such as diarrhea and nausea, which may affect how much you can eat.

However, metformin is not specifically intended or approved for weight loss purposes.

This article will discuss why you might experience weight changes on metformin and whether this means metformin could be used as a potential weight loss drug.

Scott Olson / Getty Images

In type 2 diabetes, insulin is produced in the body, but the cells are not able to respond to the insulin being released. This is known asinsulin resistance.

As a result, your cells cannot absorb sugar, so it remains in your blood and causes high blood sugar levels.Metformin can prevent high blood sugar levelsin three ways:

Weight Loss As a Side Effect of Metformin

It is clinically shown that a common side effect of metformin is weight loss.

Studies have suggested that metformin decreases appetite and changes the bacterial community of the gut.

There are several ways that metformin may contribute to weight loss.

Withleptin resistance, your brain thinks you need to eat more, even though leptin levels remain high. One study found that metformin reduced leptin resistance in pregnant women with polycystic ovary syndrome and modulated gestational weight gain.

Metformin may also cause some digestive-related side effects, such as diarrhea or nausea, which can affect appetite and food intake.

Other Potential Causes of Weight Loss

Lifestyle Changes

If you take metformin, that means you are likely also making lifestyle changes to helpmanage your diabetes.

Digestive Issues

Digestive issues can also be the reason why you are losing weight. These symptoms or diseases may affect appetite and food intake, potentially leading to weight loss in some individuals. Some digestive problems that are related to weight loss include:

Other Medications

Other medications can also cause weight loss as a side effect. For example, levothyroxine rebalances your hormones to break down food for energy, which may lead to modest weight loss.

Other medications that can cause weight loss include stimulants forattention deficit hyperactivity disorder (ADHD), such as Adderall and Concerta.

Some studies have demonstrated metformin’s potential effects on body weight. However, based on clinical studies, the amount of weight lost on metformin varies.

Another study assessed metformin’s effect on weight in 154 individuals with obesity who did not have diabetes. Over six months, those who took metformin lost around 12 to 15 pounds, on average.

In one long-term study, 28.5% of people taking metformin lost about 5% or less of their body weight after one year. However, those who lost weight on metformin had the greatest success maintaining weight loss six to 15 years after.

Additionally,there are other medications available, likeWegovy (semaglutide), that are specifically approved to help manage weight. Semaglutide has shown total body weight loss percentages of up to 11% after six months of use.

Taking any medication that can help you lose weight is not the best practice to maintain a healthy lifestyle. Therefore, it is important to consider a healthy diet and exercise plan, even if you are on a treatment for obesity.

If you do not have pre-diabetes or diabetes, your healthcare provider will most likely not prescribe metformin to help you lose weight.

One possible case a healthcare provider might consider metformin for weight loss is for people without diabetes who are on medications for schizophrenia.

This is becauseantipsychotic medications, such as clozapine and olanzapine, have a high risk of weight gain. Based on a collection of studies, metformin effectively decreased body weight in people without diabetes who have gained weight while being treated for schizophrenia.

Engaging in open and regular communication with a healthcare provider is crucial for anyone concerned about maintaining a healthy weight, regardless of whether one is worried about excessive weight loss or dealing with obesity.

Your healthcare provider can provide personalized guidance, evaluate health risks, ensure a balanced approach, monitor progress, and offer valuable support throughout the journey toward achieving and sustaining a healthy weight.

You may also want to consider speaking to a registered dietitian and nutritionist (RDN), who can help establish healthy eating practices.

Summary

While metformin has been commonly associated with weight loss, the medication is not intended to be used for weight loss purposes.

There are a few possibilities for why metformin helps you lose weight, including loss of appetite and a change of good bacteria in your stomach. Other factors other than metformin may contribute to weight loss, such as changes in diet and exercise, digestive issues, or other medications.

If you feel that you may need medication to help you achieve a healthy weight, contact your healthcare provider to discuss a personalized weight management plan.

How much weight one loses on metformin can vary. In one study, people who took metformin for six months lost 5% of their body weight.This means that, for example, someone who weighs 180 pounds would have lost 9 lbs over six months.

Yes, metformin has been used off-label to help manage weight gain related to antipsychotic medications, such as risperidone and clozapine.

In addition, you should avoid taking metformin if you have kidney disease or kidney failure.

Acknowledgement

The author would like to recognize and thank Alexya Rosas for contributing to this article.

18 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Dutta S, Shah RB, Singhal S, et al.Metformin: a review of potential mechanism and therapeutic utility beyond diabetes.Drug Des Devel Ther. 2023;17:1907-1932. doi:10.2147/DDDT.S409373Food and Drug Administration.Metformin label.LaMoia TE, Shulman GI.Cellular and molecular mechanisms of metformin action.Endocr Rev. 2021;42(1):77-96. doi:10.1210/endrev/bnaa023Yerevanian A, Soukas AA.Metformin: mechanisms in human obesity and weight loss.Curr Obes Rep. 2019;8(2):156-164. doi:10.1007/s13679-019-00335-3Vilariño-García T, Polonio-González ML, Pérez-Pérez A, et al.Role of leptin in obesity, cardiovascular disease, and Type 2 diabetes.Int J Mol Sci. 2024;25(4):2338. doi:10.3390/ijms25042338Molin J, Vanky E, Løvvik TS, Dehlin E, Bixo M.Gestational weight gain, appetite regulating hormones, and metformin treatment in polycystic ovary syndrome: a longitudinal, placebo-controlled study.BJOG. 2022;129(7):1112-1121. doi:10.1111/1471-0528.17042Silamiķele L, Silamiķelis I, Ustinova M, et al.Metformin strongly affects gut microbiome composition in high-fat diet-induced type 2 diabetes mouse model of both sexes.Front Endocrinol (Lausanne). 2021;12:626359. doi:10.3389/fendo.2021.626359Siavash M, Tabbakhian M, Sabzghabaee AM, Razavi N.Severity of gastrointestinal side effects of metformin tablet compared to metformin capsule in type 2 diabetes mellitus patients.J Res Pharm Pract. 2017;6(2):73-76. doi:10.4103/jrpp.JRPP_17_2.American Diabetes Association.Weekly exercise targets.American Diabetes Association Professional Practice Committee.8. Obesity and weight management for the prevention and treatment of type 2 diabetes:Standards of Care in Diabetes-2024.Diabetes Care. 2024;47(Suppl 1):S145-S157. doi:10.2337/dc24-S008Pearce EN.Thyroid hormone and obesity.Curr Opin Endocrinol Diabetes Obes. 2012;19(5):408-13. doi: 10.1097/MED.0b013e328355cd6cGurka MJ, Siddiqi SU, Filipp SL, Mercado R, Thompson LA, et al.Attention deficit hyperactivity disorder medications and BMI trajectories: the role of medication type, sex and age.Pediatr Obes. 2021;16(4):e12738. doi:10.1111/ijpo.12738Feng W, Gao C, Bi Y, et al.Randomized trial comparing the effects of gliclazide, liraglutide, and metformin on diabetes with non-alcoholic fatty liver disease.J Diabetes. 2017;9(8):800-809. doi:10.1111/1753-0407.12555Solymár M, Ivic I, Pótó L, et al.Metformin induces significant reduction of body weight, total cholesterol and LDL levels in the elderly - a meta-analysis.PLoS One. 2018;13(11):e0207947. doi:10.1371/journal.pone.0207947Seifarth C, Schehler B, Schneider HJ.Effectiveness of metformin on weight loss in non-diabetic individuals with obesity.Exp Clin Endocrinol Diabetes. 2013;121(1):27-31. doi:10.1055/s-0032-1327734Apolzan JW, Venditti EM, Edelstein SL, Diabetes Prevention Program Research Group, et al.Long-term weight loss with metformin or lifestyle intervention in the diabetes prevention program outcomes study.Ann Intern Med. 2019;170(10):682-690. doi:10.7326/M18-1605Ghusn W, De la Rosa A, Sacoto D, et al.Weight loss outcomes associated with semaglutide treatment for patients with overweight or obesity.JAMA Netw Open. 2022;5(9):e2231982. doi:10.1001/jamanetworkopen.2022.31982de Silva VA, Suraweera C, Ratnatunga SS, et al.Metformin in prevention and treatment of antipsychotic induced weight gain: a systematic review and meta-analysis.BMC Psychiatry. 2016;16(1):341. doi:10.1186/s12888-016-1049-5

18 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Dutta S, Shah RB, Singhal S, et al.Metformin: a review of potential mechanism and therapeutic utility beyond diabetes.Drug Des Devel Ther. 2023;17:1907-1932. doi:10.2147/DDDT.S409373Food and Drug Administration.Metformin label.LaMoia TE, Shulman GI.Cellular and molecular mechanisms of metformin action.Endocr Rev. 2021;42(1):77-96. doi:10.1210/endrev/bnaa023Yerevanian A, Soukas AA.Metformin: mechanisms in human obesity and weight loss.Curr Obes Rep. 2019;8(2):156-164. doi:10.1007/s13679-019-00335-3Vilariño-García T, Polonio-González ML, Pérez-Pérez A, et al.Role of leptin in obesity, cardiovascular disease, and Type 2 diabetes.Int J Mol Sci. 2024;25(4):2338. doi:10.3390/ijms25042338Molin J, Vanky E, Løvvik TS, Dehlin E, Bixo M.Gestational weight gain, appetite regulating hormones, and metformin treatment in polycystic ovary syndrome: a longitudinal, placebo-controlled study.BJOG. 2022;129(7):1112-1121. doi:10.1111/1471-0528.17042Silamiķele L, Silamiķelis I, Ustinova M, et al.Metformin strongly affects gut microbiome composition in high-fat diet-induced type 2 diabetes mouse model of both sexes.Front Endocrinol (Lausanne). 2021;12:626359. doi:10.3389/fendo.2021.626359Siavash M, Tabbakhian M, Sabzghabaee AM, Razavi N.Severity of gastrointestinal side effects of metformin tablet compared to metformin capsule in type 2 diabetes mellitus patients.J Res Pharm Pract. 2017;6(2):73-76. doi:10.4103/jrpp.JRPP_17_2.American Diabetes Association.Weekly exercise targets.American Diabetes Association Professional Practice Committee.8. Obesity and weight management for the prevention and treatment of type 2 diabetes:Standards of Care in Diabetes-2024.Diabetes Care. 2024;47(Suppl 1):S145-S157. doi:10.2337/dc24-S008Pearce EN.Thyroid hormone and obesity.Curr Opin Endocrinol Diabetes Obes. 2012;19(5):408-13. doi: 10.1097/MED.0b013e328355cd6cGurka MJ, Siddiqi SU, Filipp SL, Mercado R, Thompson LA, et al.Attention deficit hyperactivity disorder medications and BMI trajectories: the role of medication type, sex and age.Pediatr Obes. 2021;16(4):e12738. doi:10.1111/ijpo.12738Feng W, Gao C, Bi Y, et al.Randomized trial comparing the effects of gliclazide, liraglutide, and metformin on diabetes with non-alcoholic fatty liver disease.J Diabetes. 2017;9(8):800-809. doi:10.1111/1753-0407.12555Solymár M, Ivic I, Pótó L, et al.Metformin induces significant reduction of body weight, total cholesterol and LDL levels in the elderly - a meta-analysis.PLoS One. 2018;13(11):e0207947. doi:10.1371/journal.pone.0207947Seifarth C, Schehler B, Schneider HJ.Effectiveness of metformin on weight loss in non-diabetic individuals with obesity.Exp Clin Endocrinol Diabetes. 2013;121(1):27-31. doi:10.1055/s-0032-1327734Apolzan JW, Venditti EM, Edelstein SL, Diabetes Prevention Program Research Group, et al.Long-term weight loss with metformin or lifestyle intervention in the diabetes prevention program outcomes study.Ann Intern Med. 2019;170(10):682-690. doi:10.7326/M18-1605Ghusn W, De la Rosa A, Sacoto D, et al.Weight loss outcomes associated with semaglutide treatment for patients with overweight or obesity.JAMA Netw Open. 2022;5(9):e2231982. doi:10.1001/jamanetworkopen.2022.31982de Silva VA, Suraweera C, Ratnatunga SS, et al.Metformin in prevention and treatment of antipsychotic induced weight gain: a systematic review and meta-analysis.BMC Psychiatry. 2016;16(1):341. doi:10.1186/s12888-016-1049-5

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Dutta S, Shah RB, Singhal S, et al.Metformin: a review of potential mechanism and therapeutic utility beyond diabetes.Drug Des Devel Ther. 2023;17:1907-1932. doi:10.2147/DDDT.S409373Food and Drug Administration.Metformin label.LaMoia TE, Shulman GI.Cellular and molecular mechanisms of metformin action.Endocr Rev. 2021;42(1):77-96. doi:10.1210/endrev/bnaa023Yerevanian A, Soukas AA.Metformin: mechanisms in human obesity and weight loss.Curr Obes Rep. 2019;8(2):156-164. doi:10.1007/s13679-019-00335-3Vilariño-García T, Polonio-González ML, Pérez-Pérez A, et al.Role of leptin in obesity, cardiovascular disease, and Type 2 diabetes.Int J Mol Sci. 2024;25(4):2338. doi:10.3390/ijms25042338Molin J, Vanky E, Løvvik TS, Dehlin E, Bixo M.Gestational weight gain, appetite regulating hormones, and metformin treatment in polycystic ovary syndrome: a longitudinal, placebo-controlled study.BJOG. 2022;129(7):1112-1121. doi:10.1111/1471-0528.17042Silamiķele L, Silamiķelis I, Ustinova M, et al.Metformin strongly affects gut microbiome composition in high-fat diet-induced type 2 diabetes mouse model of both sexes.Front Endocrinol (Lausanne). 2021;12:626359. doi:10.3389/fendo.2021.626359Siavash M, Tabbakhian M, Sabzghabaee AM, Razavi N.Severity of gastrointestinal side effects of metformin tablet compared to metformin capsule in type 2 diabetes mellitus patients.J Res Pharm Pract. 2017;6(2):73-76. doi:10.4103/jrpp.JRPP_17_2.American Diabetes Association.Weekly exercise targets.American Diabetes Association Professional Practice Committee.8. Obesity and weight management for the prevention and treatment of type 2 diabetes:Standards of Care in Diabetes-2024.Diabetes Care. 2024;47(Suppl 1):S145-S157. doi:10.2337/dc24-S008Pearce EN.Thyroid hormone and obesity.Curr Opin Endocrinol Diabetes Obes. 2012;19(5):408-13. doi: 10.1097/MED.0b013e328355cd6cGurka MJ, Siddiqi SU, Filipp SL, Mercado R, Thompson LA, et al.Attention deficit hyperactivity disorder medications and BMI trajectories: the role of medication type, sex and age.Pediatr Obes. 2021;16(4):e12738. doi:10.1111/ijpo.12738Feng W, Gao C, Bi Y, et al.Randomized trial comparing the effects of gliclazide, liraglutide, and metformin on diabetes with non-alcoholic fatty liver disease.J Diabetes. 2017;9(8):800-809. doi:10.1111/1753-0407.12555Solymár M, Ivic I, Pótó L, et al.Metformin induces significant reduction of body weight, total cholesterol and LDL levels in the elderly - a meta-analysis.PLoS One. 2018;13(11):e0207947. doi:10.1371/journal.pone.0207947Seifarth C, Schehler B, Schneider HJ.Effectiveness of metformin on weight loss in non-diabetic individuals with obesity.Exp Clin Endocrinol Diabetes. 2013;121(1):27-31. doi:10.1055/s-0032-1327734Apolzan JW, Venditti EM, Edelstein SL, Diabetes Prevention Program Research Group, et al.Long-term weight loss with metformin or lifestyle intervention in the diabetes prevention program outcomes study.Ann Intern Med. 2019;170(10):682-690. doi:10.7326/M18-1605Ghusn W, De la Rosa A, Sacoto D, et al.Weight loss outcomes associated with semaglutide treatment for patients with overweight or obesity.JAMA Netw Open. 2022;5(9):e2231982. doi:10.1001/jamanetworkopen.2022.31982de Silva VA, Suraweera C, Ratnatunga SS, et al.Metformin in prevention and treatment of antipsychotic induced weight gain: a systematic review and meta-analysis.BMC Psychiatry. 2016;16(1):341. doi:10.1186/s12888-016-1049-5

Dutta S, Shah RB, Singhal S, et al.Metformin: a review of potential mechanism and therapeutic utility beyond diabetes.Drug Des Devel Ther. 2023;17:1907-1932. doi:10.2147/DDDT.S409373

Food and Drug Administration.Metformin label.

LaMoia TE, Shulman GI.Cellular and molecular mechanisms of metformin action.Endocr Rev. 2021;42(1):77-96. doi:10.1210/endrev/bnaa023

Yerevanian A, Soukas AA.Metformin: mechanisms in human obesity and weight loss.Curr Obes Rep. 2019;8(2):156-164. doi:10.1007/s13679-019-00335-3

Vilariño-García T, Polonio-González ML, Pérez-Pérez A, et al.Role of leptin in obesity, cardiovascular disease, and Type 2 diabetes.Int J Mol Sci. 2024;25(4):2338. doi:10.3390/ijms25042338

Molin J, Vanky E, Løvvik TS, Dehlin E, Bixo M.Gestational weight gain, appetite regulating hormones, and metformin treatment in polycystic ovary syndrome: a longitudinal, placebo-controlled study.BJOG. 2022;129(7):1112-1121. doi:10.1111/1471-0528.17042

Silamiķele L, Silamiķelis I, Ustinova M, et al.Metformin strongly affects gut microbiome composition in high-fat diet-induced type 2 diabetes mouse model of both sexes.Front Endocrinol (Lausanne). 2021;12:626359. doi:10.3389/fendo.2021.626359

Siavash M, Tabbakhian M, Sabzghabaee AM, Razavi N.Severity of gastrointestinal side effects of metformin tablet compared to metformin capsule in type 2 diabetes mellitus patients.J Res Pharm Pract. 2017;6(2):73-76. doi:10.4103/jrpp.JRPP_17_2.

American Diabetes Association.Weekly exercise targets.

American Diabetes Association Professional Practice Committee.8. Obesity and weight management for the prevention and treatment of type 2 diabetes:Standards of Care in Diabetes-2024.Diabetes Care. 2024;47(Suppl 1):S145-S157. doi:10.2337/dc24-S008

Pearce EN.Thyroid hormone and obesity.Curr Opin Endocrinol Diabetes Obes. 2012;19(5):408-13. doi: 10.1097/MED.0b013e328355cd6c

Gurka MJ, Siddiqi SU, Filipp SL, Mercado R, Thompson LA, et al.Attention deficit hyperactivity disorder medications and BMI trajectories: the role of medication type, sex and age.Pediatr Obes. 2021;16(4):e12738. doi:10.1111/ijpo.12738

Feng W, Gao C, Bi Y, et al.Randomized trial comparing the effects of gliclazide, liraglutide, and metformin on diabetes with non-alcoholic fatty liver disease.J Diabetes. 2017;9(8):800-809. doi:10.1111/1753-0407.12555

Solymár M, Ivic I, Pótó L, et al.Metformin induces significant reduction of body weight, total cholesterol and LDL levels in the elderly - a meta-analysis.PLoS One. 2018;13(11):e0207947. doi:10.1371/journal.pone.0207947

Seifarth C, Schehler B, Schneider HJ.Effectiveness of metformin on weight loss in non-diabetic individuals with obesity.Exp Clin Endocrinol Diabetes. 2013;121(1):27-31. doi:10.1055/s-0032-1327734

Apolzan JW, Venditti EM, Edelstein SL, Diabetes Prevention Program Research Group, et al.Long-term weight loss with metformin or lifestyle intervention in the diabetes prevention program outcomes study.Ann Intern Med. 2019;170(10):682-690. doi:10.7326/M18-1605

Ghusn W, De la Rosa A, Sacoto D, et al.Weight loss outcomes associated with semaglutide treatment for patients with overweight or obesity.JAMA Netw Open. 2022;5(9):e2231982. doi:10.1001/jamanetworkopen.2022.31982

de Silva VA, Suraweera C, Ratnatunga SS, et al.Metformin in prevention and treatment of antipsychotic induced weight gain: a systematic review and meta-analysis.BMC Psychiatry. 2016;16(1):341. doi:10.1186/s12888-016-1049-5

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