Does Metformin Help with Weight Loss?

Metformin is a medication that is used for the treatment of type 2 diabetes and prediabetes by helping to control blood sugar levels in your body.

It can also cause weight loss along with several other side effects although that is not its intended purpose.

Even though it may cause you to lose weight, it is not typically prescribed as a weight-loss drug.

In this article, we will answer all of your questions about metformin and weight loss while we discuss how metformin works, the side effects of metformin, and how much metformin costs.

What is metformin?

Metformin is a common diabetes drug prescribed to treat type 2 diabetes and prediabetes.

Type 2 diabetes, also called diabetes mellitus, is a chronic condition where the body does not properly use insulin.

Your body makes glucose, or blood sugar, from the foods you eat, and insulin is a hormone that helps glucose get into your cells to be used as energy.

If you have type 2 diabetes, your glucose levels become too high due to your cells becoming insulin resistant. The insulin resistance allows your blood glucose to build in your body which raises your blood sugar level and causes you to be diagnosed with diabetes.

Prediabetes is similar to type 2 diabetes although your blood sugar levels are not as high and the condition is reversible but it can lead to the development of diabetes.

Metformin helps to treat both of these conditions by lowering your blood sugar levels to keep them in the normal range which is also called glycemic control.

How does metformin work?

The mechanism of action for metformin is still unknown however it is thought to work by decreasing the amount of glucose that your liver produces which then increases the sensitivity of your cells to insulin and decreases the absorption of glucose from your intestine.

All of these effects help to lower your blood glucose levels and have better blood glucose control. Metformin is also thought to change the microbiota in your gut which helps your body to become more sensitive to insulin and use the glucose already in your bloodstream.

Due to metformin changing the bacteria in your gut, it is also known to have a lot of digestive issues as side effects which we will detail below.

Researchers are uncertain if these side effects cause weight loss because they decrease your appetite or if the changes in your gut bacteria make you less hungry due to the hormone leptin which makes you feel full.

When you take metformin, you and your doctor or health care provider must take into account your diet and how often you exercise because both diet and exercise can make you more sensitive to insulin and your dose of metformin needs to take this into account.

Besides type 2 diabetes and prediabetes, metformin is also used to help treat polycystic ovary syndrome (PCOS) and can also be used to combat weight gain from taking certain antipsychotic medications despite this not being its main purpose.

Is metformin an effective weight loss drug?

The short answer is no, metformin is not an effective weight loss medication even though you may lose weight while taking it.

There is a lot of research that still needs to be done on metformin and weight loss however in some studies, metformin has been linked to weight loss. In an early study published in 2008, metformin was found to help decrease weight or at least be weight neutral, meaning the subjects did not gain any weight which is far better than other drugs that cause weight gain.

Another small study of diabetics with morbid obesity found that a healthy diet while taking metformin decreased weight significantly although the sample size was small and more research is needed to draw any firm conclusions.

The Diabetes Prevention Program (DPP) has performed the most extensive study to date about metformin and weight loss for study participants with prediabetes and found that the average weight loss per person is just under five pounds when taking metformin which was more than those taking placebo pills.

These results showcase that metformin can cause weight loss; however, an average of just under five pounds is not significant enough to prescribe it solely as a weight-loss drug.

Also, more research is needed to confirm these results and metformin’s weight loss abilities.

If you take certain antipsychotic drugs there is a chance of metabolic syndrome which is a combination of high blood pressure, insulin resistance, and obesity.

The weight gain is due to elevated lipids, which are fats such as cholesterol and triglycerides, in your blood and metformin has been shown to help lower these levels and help with weight loss.

There was a double-blind placebo study performed that showed taking metformin while starting to take these antipsychotic medications reduced the weight gain of the patients in the study.

Metformin has been shown in multiple studies to encourage weight reduction as a side effect although the modest weight loss has not been significant as it is typically between 5% and 10% of your body mass.

The amount of weight you lose while taking metformin also depends on how overweight or obese you are and your diet and exercise routines.

Please talk to your doctor or healthcare provider if you think metformin may be right for you.

What are the best ways to lose weight?

The best ways to lose weight are through a healthy diet and regular exercise.

A healthy, balanced diet is key to losing weight and keeping it off. Portion control is also important as you can still gain weight with excessive food intake despite your meals being healthy.

Carb counting, where you count the number of calories and carbohydrates you have in a day, may also be beneficial if you are overweight or have prediabetes or diabetes.

You need to also try to exercise five days a week for at least 30 minutes or 150 minutes per week with exercise occurring on three or more days out of the week.

These two healthy lifestyle habits are the best ways to treat obesity by helping you lose weight and maintain a healthy weight.

If you are struggling to lose weight, please talk to your doctor or health care provider as they may be able to help.

What are the side effects of metformin?

The most common side effects of metformin include:

• Diarrhea
• Abdominal pain
• Loose stool
• Loss of appetite
• Muscle cramping
• Fever
• Difficulty breathing
• Bloating
• Indigestion
• Vomiting
• Weight loss
• Heartburn

There are other adverse effects too and if you experience any please consult with your doctor or health care professional.

Metformin may also interact with alcohol so you need to limit your alcohol intake while on it and it also may interact with aspirin or other medications which is why it is important to disclose any medications you may be taking to your doctor before you start metformin.

Taking too much metformin can also cause lactic acidosis which is when your blood becomes too acidic and can cause a heart attack or kidney failure.

The symptoms of lactic acidosis are similar to the ones above and can come on suddenly which makes it important to seek medical attention if you have them. These symptoms include:

• Extreme tiredness
• Weakness
• Nausea
• Vomiting
• Stomach pain or upset stomach
• Decreased appetite
• Shallow rapid breathing
• A feeling of general discomfort
• Feeling lightheaded
• Pale skin
• Muscle pain or cramps
• Feeling of cold or numbness in your extremities

Please seek immediate medical attention if you have these symptoms.

Who needs to avoid taking metformin?

Avoid metformin if you have or have had any of the following conditions:

• Chronic kidney disease
• Heart disease or heart attack
• Stroke
• Diabetic ketoacidosis
• Anemia
• Liver disease
• Coma
• B-12 deficiency

Always disclose your medical history to your doctor before taking metformin as they will be able to assess if metformin is right for you.

What is the dosage and price of metformin?

The dosage for metformin will be determined by your doctor and the cost will depend on if your insurance covers it and also if you get the generic form or brand name form of metformin but is typically around $5-$15 per month.

It is available under the brand names Fortamet, Glucophage, Glucophage XR, Glumetza, and Riomet.

Summary

Metformin is a prediabetes and diabetes medication used to help with blood sugar control and has been shown in some studies to also help with weight loss.

The metformin-induced weight loss is usually not very significant and more research is needed to determine if it is a viable treatment option to help you lose body weight and as a treatment for obesity.

It is important to talk to your doctor before taking metformin as there are some conditions in which metformin needs to be avoided and it can also interact with other medications.

The dosage and price of metformin will be determined by your doctor although metformin typically costs no more than $15 per month.

If you have any more questions, please talk to your doctor or health care provider about whether metformin treatment is right for you.

References and sources:

NIH

• Metformin
• Metformin and body weight
• Metformin: Mechanisms in Human Obesity and Weight Loss
• Long-term safety, tolerability, and weight loss associated with metformin in the Diabetes Prevention Program Outcomes Study
• Metformin in prevention and treatment of antipsychotic induced weight gain: a systematic review and meta-analysis

Mayo Clinic

• Metformin (Oral Route)

WebMD 

• Does Metformin Cause Weight Loss?

Fact Checked and Editorial Process

Diabetic.org is devoted to producing expert and accurate articles and information for our readers by hiring experts, journalists, medical professionals, and our growing Diabetic.org community. We encourage you to read more about our content, editing, and fact checking methods here. This was fact checked by Jacqueline Hensler and medically reviewed by Dr. Angel Rivera.