Metformin and other medications for weight loss against a red background

Does Metformin Cause Weight Loss?

Written on September 13, 2023 by Theresa Vuskovich, DMD. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Table of contents

Key points:

  • Metformin is the first-line therapy for individuals diagnosed with type 2 diabetes.[1-5]
  • Metformin is not a weight loss drug, but taking metformin can cause weight loss for some people.[1-5]
  • During a 16-week clinical trial, individuals with type 2 diabetes taking 1000 mg of metformin twice daily lost, on average, 2.2 lbs.[4]
  • Metformin weight loss depends on your ability to adhere to the medication and healthy lifestyle choices.[3-5]
  • Metformin may cause gastrointestinal discomfort, including diarrhea, nausea, and vomiting.[4,5]

Metformin is one of the most commonly prescribed medications to lower blood sugar.[1-5] The U.S. Food and Drug Administration (FDA) approved metformin in 1994 for the treatment of type 2 diabetes (T2D).[2] Metformin is prescribed as a monotherapy or in combination with other drugs to treat T2D.[1-5] For many people with T2D, weight loss is a struggle, and metformin may help. This article explains metformin and answers the question, “Does metformin cause weight loss?”

What is Metformin Used For?

Metformin is used for the treatment of T2D.[1-6] When an individual with T2D is diagnosed, metformin is the first drug prescribed for treatment.[3] Metformin lowers blood sugar and may prevent some of the common complications associated with T2D, including heart disease, kidney problems, and neurological conditions.[3]

Metformin increases insulin secretion in the pancreas and improves the uptake of glucose in your muscles.[1] As a result, you have less sugar in your blood, which lowers your risk of diseases associated with T2D.[1-5] One way to measure your blood sugar levels is an A1C test, a test that measures your blood sugar over the past three months. Metformin may reduce A1C by 1.12% as a monotherapy and by 0.95% when combined with other drugs. [3]

Metformin is also prescribed off-label for individuals with polycystic ovary syndrome (PCOS) and prediabetes.[2] One in three Americans have prediabetes, a condition characterized by high blood sugar levels but not high enough to receive a T2D diagnosis. Prediabetes often has no symptoms, so you may not be aware that you have it.

Metformin and Prediabetes

According to the American Diabetes Association (ADA), metformin may prevent the progression of prediabetes into type 2 diabetes in patients with a body mass index (BMI) greater than 35, individuals younger than 60, and women with a history of gestational diabetes.[3] Blood sugar control and weight loss are still dependent on a healthy lifestyle, even when metformin is prescribed for prediabetes.[3-5]

Metformin and Heart Disease

Research suggests metformin may lower your heart disease risk if you have T2D.[3,5] According to the U.K. Prospective Diabetes Study (UKPDS), metformin may decrease macrovascular complications caused by type 2 diabetes by 30%.[3] A macrovascular vessel refers to any large vessel in your body, including your coronary arteries, which supply blood to your heart.[3] Some studies indicate metformin has little or no effect on reducing the risk of heart disease, and more research is needed in order to establish metformin's cardiovascular benefits.[3]

Metformin and Weight Loss

Even though metformin is not FDA-approved as a weight loss drug, metformin can help some individuals with prediabetes and T2D lose weight.[3,5] Metformin is classified as a diabetic drug that is weight neutral or may aid in weight loss.[5] Studies indicate weight loss associated with metformin depends on your ability to adhere to the medication and maintain a healthy lifestyle.[3,5] Patients taking metformin lost 0.6%-13% of their starting weight during clinical trials and observational studies.[3,5]

Everlywell Weight Loss Support

How Does Metformin Help You Lose Weight?

How metformin helps you lose weight is not completely understood.[2,3,5] Some studies suggest metformin may lower your appetite, resulting in weight loss.[2,3] The Diabetes Prevention Program (DPP) is a clinical study following individuals with T2D and prediabetes.[3,5] The DPP study aimed to learn how diabetic drugs and lifestyle choices affect weight in people with prediabetes and type 2 diabetes.

During the DPP, individuals treated with metformin lost an average of 2.5% of their starting weight.[5] Those who adhered to the medication and lifestyle modifications were more likely to lose weight. More adherent patients reduced their BMI by 3.5%.[2]

Metformin dosage may also affect the degree of weight loss.[4,5] During a 16-week study, participants with T2D taking 1000 mg twice daily lost an average of 2.2 pounds (lbs).[4] Participants taking 500 mg once daily lost, on average, 1.3 lbs.[4]

How Much Weight Will You Lose Taking Metformin?

Metformin may help you lose weight, but how much depends on your starting weight, comorbidities, medication adherence, and lifestyle choices.[1-5] Some diabetic drugs, such as insulin and sulfonylureas, can cause weight gain and may interfere with weight loss.[5] As a result, an individualized weight loss plan is best when you have T2D or prediabetes. For help with your weight loss journey, consult a healthcare provider to determine which medications and lifestyle modifications are best for you.

What You Need to Know if You Take Metformin

While metformin is considered a safe and effective drug for those with T2D, there are some risks and side effects to consider. If you are taking or planning to take metformin, it is important to know the following [1-5]:

  • Metformin increases your risk of a B12 deficiency. Vitamin B12 plays a crucial role in red blood cell production, DNA synthesis, and nerve function.
  • Metformin increases the risk of lactic acidosis, a condition caused by the buildup of lactic acid in your blood. The most common symptoms of lactic acidosis are fatigue, muscle pain, abdominal pain, and breathing difficulties. Call 911 immediately if you think you may have lactic acidosis, as it is life-threatening. Individuals with a history of kidney or liver disease and who are 65 years and older are at a greater risk of lactic acidosis.
  • Nausea, vomiting, and diarrhea are metformin's most common side effects. Headaches can also occur. These symptoms are more likely to occur when you begin taking metformin. If symptoms persist, your healthcare provider may lower your dosage.
  • Metformin can cause a metallic taste in your mouth when you start taking it.
  • There is a risk of hypoglycemia (low blood sugar) when taking metformin, especially if you drink alcohol, don't eat enough, or take other diabetic medications.

Everlywell Helps You Get Your Weight Down to a Science

Everlywell's option for weight loss help online provides you with the tools you need to manage your weight and T2D. Virtual care visits with a licensed nurse practitioner will help determine which tests, lifestyle changes, and medications are necessary for you to feel your best. Three-month or 12-month programs are available. While medications to assist with weight loss are available, they are not guaranteed when you join the program. Your healthcare provider wants to ensure that you lose weight in a safe and healthy manner.

When you enroll in the program, you gain access to clinician-written lifestyle support and Everlywell’s at-home lab tests and supplements, including the Heart Health Test, Cholesterol & Lipids Test, HbA1c Test, daily multivitamin gummy, or omega-3 fish oil. The 12-month program provides tests every quarter for you to track your biomarkers and progress. The Weight Care+ program helps you monitor your T2D and weight in order to achieve your weight loss goals.

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  1. Dong Y, Qi Y, Jiang H, et al. The development and benefits of metformin in various diseases [published online ahead of print, 2023 Jul 4]. Front Med. 2023;10.1007/s11684-023-0998-6.
  2. Yerevanian A, Soukas AA. Metformin: Mechanisms in human obesity and weight loss. Curr Obes Rep. 2019;8(2):156-164.
  3. Vieira IH, Barros LM, Baptista CF, Rodrigues DM, Paiva IM. Recommendations for practical use of metformin, a central pharmacological therapy in type 2 diabetes. Clin Diabetes. 2022;40(1):97-107.
  4. Glucophage® (metformin hydrochloride) tablets prescribing information. Food and Drug Administration.,021202s021s023lbl.pdf. Accessed July 28, 2023.
  5. Barlow B. Management of obesity in patients with diabetes. U.S. Pharmacist. Published November 19, 2021. Accessed June 13, 2023.
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