A drug called metformin is used by doctors to treat type 2 diabetes. This drug helps to lower blood sugar in patients with the condition when used with other medications and insulin.

Although the FDA has not approved the use of metformin for women with polycystic ovarian syndrome, doctors can sometimes prescribe it for this purpose.

The FDA has not approved metformin as a weight loss drug for people who are overweight or obese.

How Metformin Works

Metformin helps to lower blood sugar levels by decreasing the amount of glucose that is released from the liver, and by helping the body’s existing insulin work more effectively.

Similarly, losing weight can help to improve your blood pressure and cholesterol, which also helps to decrease your risk of developing heart disease. Your risk of developing diabetes complications such as heart disease, stroke, neuropathy, and even retinopathy substantially decrease as your body is better able to metabolize glucose. Losing weight can also help improve your blood pressure and cholesterol, further decreasing your risk of heart disease.

Does Metformin Cause Weight Loss?

Non-diabetic people have also lost weight from taking metformin.

A study showed that overweight or obese people who had insulin resistance lost weight while taking metformin.

Though there is some evidence that metformin causes weight loss, it is unclear how it works.

There is some debate among researchers as to whether the drug reduces appetite or changes the way the body stores and uses fat.

Doctors usually suggest making some dietary and lifestyle changes in addition to taking metformin or other medications for type 2 diabetes or prediabetes. If a person follows the recommendations, they are likely to lose weight.

If you only take metformin and don’t make any other lifestyle changes, you probably won’t see any weight loss.

To lose weight while taking metformin, people should eat a healthy diet with plenty of nutrients and not too many calories. They should also exercise regularly.

If someone doesn’t follow other healthy habits, they likely won’t lose weight while taking metformin.

Metformin can help you lose weight for several reasons:

Better Blood Sugar Control

Metformin is a medication that is taken by people with type 2 diabetes. It helps to improve insulin sensitivity and blood sugar control. It is thought that people who have higher blood sugar levels despite also having excess insulin in their bloodstream may see modest reductions in body weight when they take Metformin.

When insulin resistance decreases, weight often also decreases. This is mostly because the body will stop over-releasing insulin into the bloodstream, and their bodies will start to metabolize glucose appropriately.

However, a very small proportion of the population may gain weight initially, especially if they had undiagnosed type 2 diabetes or were in diabetic ketoacidosis (DKA) at diagnosis.

This occurs very rarely because most people with type 2 diabetes produce insulin when they are first diagnosed. Their hba1c is only slightly elevated. Most people with type 2 diabetes are not in DKA at diagnosis; their bodies produce insulin to keep them out of DKA, but they are resistant to the insulin that is being released by their pancreas.

Reduced Hunger Cues

A side effect of the drug is that people tend to experience reduced hunger, as it lowers the amount of insulin in the blood and reduces blood sugar spikes.

The group that took the highest amount of Metformin had less hunger before and after meals than the other groups.

The group was also more likely to eat less food than the other two groups.

If you reduce your calorie intake by just a few hundred calories every day, you will see moderate weight loss over time. For example, eating 200 fewer calories per day for only 18 days can help you lose 1 pound of body fat (which is equal to 3,500 calories).

If you eat 200 fewer calories every day for a year, you could lose more than 20 pounds. Making small, subtle changes can have a big impact.

Healthier Lifestyle Habits 

Metformin may help people lose weight if they change their diet and exercise more.

If you start taking Metformin without making any other lifestyle changes, you probably won’t lose much weight.

The following strategies will help accelerate your weight loss if you’ve just started on a Metformin regimen: 

  • Exercise for 30 or more minutes per day, most days of the week
  • Incorporate resistance training 2-3 times per week 
  • Switch from all sugar-sweetened beverages to water or other no-calorie drinks
  • Increase your protein intake and lower your added sugar and refined carbohydrate intake 
  • Eat plenty of healthy fruits and vegetables
  • Increase your fiber intake 

When creating an eating and activity plan, work with your doctor to find a plan that will fit your lifestyle.

Gastrointestinal Upset 

An upset stomach with nausea, vomiting, and diarrhea can occur as a side effect of taking Metformin, and can sometimes contribute to weight loss, especially when treatment is first started.

A study published in the Journal of Research in Pharmacy Practice found that gastrointestinal upset is the most common complaint among patients who start taking Metformin in tablet form.

A side effect of Metformin is that it can cause GI problems that affect up to 63% of people who take it. These problems can include bloating, nausea, and diarrhea, which can be so troublesome that you may not want to eat, and as a result, you may lose weight.

If you feel at any point that your weight loss is dangerous or you are becoming dehydrated, contact your doctor immediately or go to the nearest emergency room.

What Is the Correct Dosage to Experience Weight Loss?

The Mayo Clinic states that patients who are taking the extended-release oral tablets usually start at a dosage of 500 to 1000 milligrams per day. The dosage is then increased incrementally until it reaches a maximum of 2500 milligrams per day.

If you want to take Metformin for weight loss, you should speak to your doctor to figure out what dose you should start with.

Do not increase your dose without speaking to your doctor first, as you may experience severe side effects such as nausea, vomiting, diarrhea, bloating, and muscle weakness.

What Is the Average Weight Loss With Metformin?

After taking Metformin for a year, most people only lose 4-7 pounds. Although some people think of Metformin as a weight loss pill, it typically doesn’t help people lose a large amount of weight.

If you are struggling to lose weight because of insulin resistance, you may want to consider making lifestyle changes, such as altering your diet and adding regular exercise. You should talk to your doctor about whether or not you should also take Metformin to help with weight loss.

However, Metformin will not cause substantial weight loss on its own.

What to Do if You Are Losing Too Much Weight on Metformin 

If you are taking Metformin for insulin resistance and you feel like you are losing too much weight, don’t worry. Any initial side effects, such as gastrointestinal discomfort, typically go away over time.

There may be other causes contributing to your weight loss, such as:

  • Higher-than-normal blood sugar levels
  • Ketones in your urine 
  • Other medications (thyroid or cancer drugs like chemotherapy, for example) 
  • Chronic diarrhea 
  • Stress 
  • Anxiety 
  • Irritable Bowel Syndrome (IBS)
  • Food allergies 
  • Food intolerances, like Celiac Disease 
  • Depression 
  • Infection

If you are losing weight for no apparent reason, you should call your doctor right away.

The healthcare team will be able to help you if you’re having any problems with Metformin and potentially stop your treatment if necessary.

Can I Take Metformin for Weight Loss Without Having Diabetes?

In some instances, Metformin may be prescribed to people who do not have diabetes in order to help with either prediabetes or insulin resistance. In these cases, weight loss is a side effect of the medication improving one’s insulin resistance.

If you are experiencing insulin resistance and/or decreased insulin sensitivity, you should talk to your doctor.

If you don’t have diabetes or insulin resistance, a doctor may prescribe Metformin to help with weight loss.

There are fewer peer-reviewed studies available on the success of using Metformin off-label, but many people have reported success when taking Metformin and making lifestyle changes, such as eating a healthier diet and exercising more.

The FDA has not metformin for weight loss. However, some doctors will prescribe it to people who are overweight or obese and have type 2 diabetes or prediabetes.

If you are prescribed metformin, it is important to also adopt other healthful habits to support weight loss, such as following a nutrient-rich, low-calorie diet and getting regular exercise.

Metformin is not a drug that will cause you to lose weight quickly. It is more likely that people who take metformin will lose weight gradually over time.

People who stop taking metformin may regain any weight they lost while taking the drug.

Risks and Side Effects

The FDA has issued its most serious warning level about metformin tablets due to the potential for dangerous side effects.

Lactic acidosis is a rare but potentially fatal side effect of metformin. It occurs when there is an accumulation of lactic acid in the blood, which can cause organ failure and death.

A person should go to the emergency room for treatment immediately if they are taking metformin and experience any of the following symptoms:

  • weakness
  • difficulty breathing
  • tiredness
  • a sense of dizziness
  • unexplained or unusual muscle pain,
  • unusual sleepiness
  • stomach pain
  • nausea or vomiting
  • slow or irregular heartbeat

People at the most risk of developing lactic acidosis include:

  • people who use or abuse alcohol while taking metformin
  • people with liver problems
  • people with kidney problems

A person’s blood sugar levels can drop to unsafe levels, which is a serious side effect.

If a person’s blood sugar drops too low, they are at risk for:

  • seizures
  • passing out
  • brain damage
  • death

If you have a low blood sugar reaction, you need to start treatment immediately to avoid some of the more serious side effects. Treatment consists of taking 15 to 20 grams (g) of glucose. This can be done in several ways, including sugary drinks and hard candies.

Symptoms of low blood sugar may include:

  • drowsiness
  • irritability
  • headache
  • weakness
  • confusion
  • feeling shaky
  • hunger
  • increased heart rate
  • sweating
  • dizziness

There are other, less serious side effects that metformin may cause as well. Some of the side effects a person may experience include:

  • gas
  • diarrhea
  • nausea
  • heartburn
  • stomach pain

Other Ways to Lose Weight

There are many ways to lose weight without using medication. Most of them include making reasonable diet and lifestyle changes.

The following steps can help a person start losing weight:

  • follow a healthful diet based on eating plenty of fruits and non-starchy vegetables
  • getting at least 30 minutes of cardiovascular exercise five times a week
  • adding strength-training exercises to build muscle
  • drinking plenty of water
  • limiting sugar
  • getting enough sleep
  • keeping a food journal to track diet
  • getting support from friends and family

Some people who are obese and unable to lose weight in other ways may be suggested to have weight loss surgery.

When to See a Doctor

If you are overweight or obese and want to lose weight, you should talk to a doctor. They will be able to recommend the best way to lose weight safely.

If you have tried unsuccessfully to lose weight, you should consult a doctor.

If you have prediabetes or type 2 diabetes, you should see a doctor on a regular basis.


Usage of metformin may be considered for people with type 2 diabetes to help control their blood sugar levels.

While metformin may lead to weight loss as a side effect, researchers are still not clear on whether or not it has an actual impact on weight. It is possible that any weight loss experienced by people with type 2 diabetes is due to lifestyle changes rather than the medication itself.

If you are not obese and don’t have type 2 diabetes, then you should probably try to lose weight the old-fashioned way—through diet and exercise. If that doesn’t work, you might want to explore other options, such as medications or weight-loss procedures.


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About Rhoda ...

Rhoda is an award-winning dietitian, mature age model, and CEO of Sayvana Women.  

She is the creator of the Elegant Eating Solution, an affordable program that helps women avoid weight regain and feel great about themselves, without restrictive eating.

Elegant Eating is based on the science of protein leverage and follows the unique R.E.M.A.P approach to successful aging.

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