Signs Metformin Is Working For Weight Loss: 5 Signs To Look For On Your Journey In 2024

signs metformin is working for weight loss
Look for indicators that metformin is working for weight loss. Photo: mapo_japan/Shutterstock

Each article is created without any external influence. When you use our provided links to buy products, we receive a commission as an affiliate. To understand how we generate revenue, please read our advertising disclaimer.

What are the signs metformin is working for weight loss? To answer this, we must first understand that metformin is not a weight loss medication. Metformin is FDA-approved to treat type 2 diabetes.[1] However, weight loss may be experienced by those taking metformin.

Positive changes in diabetes biomarkers, such as improved insulin sensitivity and lower blood sugar levels, can indicate that metformin works for diabetes. Because diabetes and weight[2] gain often go hand-in-hand, the signs that metformin is working for diabetes may also indicate that it can work for human obesity, as well.

The Diabetes Prevention Program outcomes showed that metformin treatment is effective at delaying the onset of diabetes,[3] so it can be used in prediabetes and to prevent the onset of gestational diabetes.

Conversely, when there are no improvements in these biomarkers, this may indicate that metformin is not working for diabetes or weight loss.

What Are The Signs That Metformin Is Working?

A sure sign that metformin is working specifically for weight loss is weight reduction. However, metformin is FDA-approved to treat type 2 diabetes,[4] not for weight loss.

Because type 2 diabetes and weight gain are often linked,[5] improvements in type 2 diabetes may initiate weight loss, as well. Signs that metformin is working include:

  • Improved insulin sensitivity.
  • Lower blood sugar levels.
  • Reduced appetite.
  • Lower HbA1c levels.
  • Reduced weight.

Signs Metformin Is Working For Weight Loss

Losing weight and a decreased food intake are sure signs that metformin is working for weight loss. It may take some time to see results, even when taking metformin along with practicing healthy lifestyle habits. One study found an average weight loss of 13 pounds over the course of 28 weeks.[6]

Aside from weight loss, there are other signs that metformin is working for type 2 diabetes, such as better glucose control, which could potentially assist in weight loss when combined with lifestyle intervention.

Improved Insulin Sensitivity

While taking metformin, you may have improvements in insulin sensitivity.[7] Insulin is produced in response to eating. Insulin carries glucose from food and moves it into our cells for energy.

However, insulin resistance[8] causes a muted response to insulin; this results in excess glucose in the bloodstream. Insulin resistance is often correlated with weight gain[9] and obesity.

It can be difficult to measure[10] insulin resistance and, therefore, difficult to measure if your insulin sensitivity is changing. Most insulin resistance tests are complex and used for research rather than in doctor’s offices. However, if you experience weight loss, it may indicate your insulin sensitivity is improving.

Lower Blood Sugar Levels

If your blood sugar levels have decreased since starting metformin, it is a good indicator that the medication works. Conversely, if your blood sugar levels are not improving or have become higher since starting metformin, this may indicate that you are not responding optimally to the medication or the dose is too low.

If metformin is combined with other antidiabetic agents, such as insulin, the risk for hypoglycemia increases. Metformin itself does not usually cause low blood sugar, but there is an increased risk of hypoglycemia when combined with other drugs used to treat high blood sugar.

Reduced Appetite

signs metformin is working for weight loss
You may experience reduced appetite on metformin. Photo: Goksi/Shutterstock

Metformin may initiate weight loss via appetite reduction.[6] Less caloric intake can lead to weight loss. Among several mechanisms of appetite suppression, metformin has been shown to reduce appetite via the gut-brain axis.

Specifically, it can suppress[6] lactate production post-meal, increase the production of incretins, increase leptin sensitivity, and suppress hypothalamic release of appetite-stimulating neurochemicals.

If your appetite is reduced from taking metformin, this can help weight loss efforts. Reducing portion sizes is one way to lose weight without exercising. Calculating net carbs for weight loss can also help with this process. However, it is important to consider other healthy lifestyle habits for weight loss, such as adequate sleep, hydration, and a nutritious hypocaloric diet.

Lower HbA1c Levels

Metformin has been shown to lower HbA1c levels[11] in people with type 2, as well as those with type 1 diabetes. HbA1c tests give a wider picture of blood glucose levels[12] over a two or three-month period. If your HbA1c levels improve on metformin, this shows signs of success.

However, if your HbA1c levels increase while taking metformin, your body may not respond to the medication as it should. This should be brought to your health provider’s attention.

Reduced Weight

signs metformin is working for weight loss
You may notice a reduction in weight on metformin. Photo: New Africa/Shutterstock

The most noticeable marker of whether metformin works for weight loss is weight loss. This can mean decreased body weight, waist or hip size, or body mass index.[13] A BMI over 25 indicates being overweight, and a BMI over 30 indicates obesity.

However, weight loss is not a guaranteed outcome of taking metformin; metformin is FDA-approved for type 2 diabetes. Furthermore, without attention to a healthy diet and lifestyle, it is possible to gain weight, rather than lose it, while taking metformin.

If your weight, body size, or BMI increases while taking metformin, discuss this with your registered dietitian and healthcare provider.

Metformin may be prescribed in conjunction with certain medications, such as with antipsychotic-induced weight gain. Metformin treatment in conjunction with antipsychotics[14] may prevent the drug-related weight gain often seen regardless of food intake.

Why Does Metformin Cause Weight Loss?

Metformin works in several ways to initiate weight loss. The most prominent mechanism is by decreasing appetite.[6] Indirectly, metformin may decrease appetite via unpleasant gastrointestinal side effects, such as bloating and nausea.

Metformin may also modulate the gut microbiome, increasing beneficial bacteria.[15] This can initiate and help sustain weight loss. Metformin may also improve fat metabolism,[16] which allows the body to process fat quicker and more efficiently.

Ask your doctor about an appropriate dosage of metformin for weight loss. The starting dose[17] is 500 milligrams a day and can increase up to 2,000 milligrams a day.

Additionally, metformin may not be right for everyone. If you are not getting the weight loss results you want from metformin, ask your doctor about taking other diabetes medications or weight loss vitamins, either in addition to or instead of metformin.

It’s important to support weight loss efforts holistically, such as doing cardio exercises routinely, moderating your carbohydrate intake, and drinking enough water. You may wish to add spices[18] such as ginger and cinnamon to your water to make a detox water which can help enhance weight loss benefits.

Can People Without Diabetes Take Metformin?

Yes. Metformin is FDA-approved for type 2 diabetes and may be prescribed for women with gestational diabetes.[19] Metformin can also be prescribed to prevent diabetes. However, people without diabetes may be prescribed metformin by their doctors for other reasons.

For example, metformin lowers[20] low-density lipoprotein cholesterol. Thus, it’s beneficial for treating dyslipidemia in cardiac patients who have diabetes.

Studies indicate the benefits of using metformin to treat PCOS or polycystic ovarian syndrome.[21] This is because insulin resistance is a condition commonly associated with PCOS. Metformin can help mitigate insulin resistance, reduce androgen levels, and improve weight loss, thus improving PCOS symptoms.

Despite metformin having weight loss and diabetes benefits, and although it is safe for pregnant women, it may not be suitable for everyone. Metformin should be avoided by anyone with heart failure,[22] as well as those with liver or kidney problems. Metformin can have serious side effects,[23] including gastrointestinal distress and vitamin B12 deficiency.


Metformin is FDA-approved to treat type 2 diabetes. However, it may be used for other purposes, including weight loss. Signs that metformin is working or can work for weight loss include lower blood sugar levels, decreased appetite, lower HbA1c levels, and improved insulin sensitivity. If these biomarkers don’t improve, this may indicate that metformin is not working.

When taking metformin, a reduction in weight, BMI, or waist circumference are more noticeable signs that the medication is working for weight loss. This is a good indication that metformin is also working for diabetes.

Make sure to tackle weight loss gradually and holistically. Address lifestyle changes such as eating a healthy diet and exercising, in addition to taking medication.

Frequently Asked Questions

How quickly do you see weight loss with metformin?

This varies from person to person. Studies have shown that an average weight loss of 13 pounds over 28 weeks was achieved by taking metformin. However, these results can be influenced by other lifestyle factors such as diet and exercise. 

How much weight can you lose in a month on metformin?

Based on the average weight loss of 13 pounds in 28 weeks while taking metformin, it may be possible to lose about six or seven pounds in one month. However, individual results will vary, and metformin should not replace healthy eating and exercise.

Does metformin 500 mg make you lose weight?

It may. The starting dose of metformin is 500 milligrams a day and may increase to 2,000 milligrams a day. Some people may require higher dosages than others to achieve weight loss.

Does metformin make you sleepy?

Metformin may cause vitamin B12 deficiency which may cause feelings of tiredness and fatigue. If you experience fatigue from taking metformin, alert your medical provider.

Does metformin speed up your metabolism?

No, it shouldn’t affect energy expenditure. Metformin provides blood sugar control and improved insulin sensitivity but does not increase calorie burn.

If I lose weight on metformin, will the weight stay off?

Not necessarily. There’s no evidence to suggest that metformin permanently affects the body. Weight loss may only be possible for as long as you are taking metformin. Additionally, sustained weight loss may depend on your other lifestyle habits.

How do I know if metformin is not working for weight loss?

Metformin should reduce blood sugar levels and decrease appetite, as well as improve insulin sensitivity. Via these mechanisms, metformin can assist with weight loss. If these biomarkers do not improve or worsen, this may indicate that metformin is not working.

Do I have to have diabetes to take metformin for weight loss?

No. Metformin is FDA-approved for type 2 diabetes. However, it may be prescribed for other purposes, such as to reduce weight or manage PCOS. However, it may only be covered by insurance if it is prescribed for type 2 diabetes.  

+ 23 Sources

EHproject has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We work mostly with peer-reviewed studies to ensure accurate information. We avoid using tertiary references. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

  1. NHS Choices (2023). About metformin. [online] Available at:
  2. CDC (2021). Healthy Weight . [online] Centers for Disease Control and Prevention. Available at:
  3. (2022). Diabetes Prevention Program (DPP). [online] Available at:,of%20developing%20diabetes%20by%2058%25.
  4. (n.d.). Enforcement Reports. [online] Available at:
  5. Abdullah Saleh Algoblan, Al-Alfi, M.A. and Muhammad Zargham Khan (2014). Mechanism linking diabetes mellitus and obesity. Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy, [online] pp.587–587. doi:
  6. 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:
  7. Herman, R., Nika Aleksandra Kravos, Mojca Jensterle, Andrej Janež and Dolžan, V. (2022). Metformin and Insulin Resistance: A Review of the Underlying Mechanisms behind Changes in GLUT4-Mediated Glucose Transport. International Journal of Molecular Sciences, [online] 23(3), pp.1264–1264. doi:
  8. CDC (2022). Insulin Resistance and Diabetes. [online] Centers for Disease Control and Prevention. Available at:’t%20clear%20exactly,resistance%20by%20looking%20at%20them.
  9. Verkouter, I., Noordam, R., Saskia le Cessie, Rob, Lamb, H.J., Rosendaal, F.R., Diana van Heemst and Renée de Mutsert (2019). The Association between Adult Weight Gain and Insulin Resistance at Middle Age: Mediation by Visceral Fat and Liver Fat. Journal of Clinical Medicine, [online] 8(10), pp.1559–1559. doi:
  10. and, D. (2023). Insulin Resistance & Prediabetes. [online] National Institute of Diabetes and Digestive and Kidney Diseases. Available at:,A1C%20test%20to%20diagnose%20prediabetes.
  11. Katsiaryna Sikorskaya, Iwona Zarzecka, Uzoamaka Ejikeme and Russell, J. (2021). The use of metformin as an add-on therapy to insulin in the treatment of poorly controlled type 1 diabetes mellitus in adolescents. Metabolism Open, [online] 9, pp.100080–100080. doi:
  12. (2022). Hemoglobin A1C (HbA1c) Test. [online] Available at:
  13. CDC (2022). Body Mass Index (BMI) . [online] Centers for Disease Control and Prevention. Available at:
  14. Varuni de Silva, Chathurie Suraweera, S.S. Ratnatunga, Madhubhashinee Dayabandara, Nimali Wanniarachchi and Raveen Hanwella (2016). Metformin in prevention and treatment of antipsychotic induced weight gain: a systematic review and meta-analysis. BMC Psychiatry, [online] 16(1). doi:
  15. Zhang, Q. and Hu, N. (2020). Effects of Metformin on the Gut Microbiota in Obesity and Type 2 Diabetes Mellitus. Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy, [online] Volume 13, pp.5003–5014. doi:
  16. He, L. (2020). Metformin and Systemic Metabolism. Trends in Pharmacological Sciences, [online] 41(11), pp.868–881. doi:
  17. NHS Choices (2023). How and when to take metformin. [online] Available at:
  18. Chandana Deekshith, Markandeya Jois, Radcliffe, J. and Thomas, J. (2021). Effects of culinary herbs and spices on obesity: A systematic literature review of clinical trials. Journal of Functional Foods, [online] 81, pp.104449–104449. doi:
  19. Hyer, S., Balani, J. and Shehata, H. (2018). Metformin in Pregnancy: Mechanisms and Clinical Applications. International Journal of Molecular Sciences, [online] 19(7), pp.1954–1954. doi:
  20. Szu Han Lin, Po Chung Cheng, Tu, S., Shang Ren Hsu, Yun Chung Cheng and Yu Hsiu Liu (2018). Effect of metformin monotherapy on serum lipid profile in statin-naïve individuals with newly diagnosed type 2 diabetes mellitus: a cohort study. PeerJ, [online] 6, pp.e4578–e4578. doi:
  21. Johnson, N. (2014). Metformin use in women with polycystic ovary syndrome. PubMed. [online] doi:
  22. NHS Choices (2023). Who can and cannot take metformin. [online] Available at:,your%20circulation%20or%20breathing%20difficulties.
  23. NHS Choices (2023). Side effects of metformin. [online] Available at:,vitamin%20B12%20supplements%20will%20help.


A health coach specializing in Integrative Nutrition, I approach wellness with a holistic and functional medicine perspective. As a writer, I simplify intricate topics such as nutrition, gut and hormone health, mental well-being, and spiritual health,… See More