While these don’t always affect everyone taking the medication, there is one side effect that many wonder about: if it will aid in their weight loss goals. The relationship between metformin and weight loss isn’t crystal clear, but here’s a look at what could trigger those pounds to shed and your waist to shrink while taking the medication.
What is Metformin?
“Metformin is a medication most commonly used for treatment of diabetes or pre-diabetes—however, it can be used for a variety of conditions. In general, it decreases insulin resistance, which helps our bodies respond to insulin more efficiently,” explains Kay Lovig MD, Section Chief Division of Endocrinology, White Plains Hospital. Metformin is also occasionally used use for PCOS, or polycystic ovary syndrome, notes Marcio L Griebeler, MD, Director of the Obesity Center with Cleveland Clinic’s Endocrinology & Metabolism Institute.
Can You Lose Weight By Taking Metformin?
It’s a toss up of answers, depending on who you ask. A diabetes prevention program outcomes study found that metformin can help some people lose weight, but it’s not clear how or why it may cause you to drop some pounds. The study shows metformin produces a significant reduction in body weight and waist circumference gradually over the course of one to two years and the average was anywhere from four to seven pounds. One theory is it may reduce your appetite, causing you to eat less, and it also may change the way your body uses and stores fat. Dr. Griebeler says it’s not an FDA-approved drug for weight loss, although some doctors do prescribe it for weight loss. “There are many other medications that are very effective for weight loss. Metformin should cause some weight loss, but it can be very effective in patients taking other medications that cause weight gain because it will counteract,” Dr. Griebeler adds. Meanwhile, Dr. Lovig says metformin typically does not cause significant weight loss in the majority of patients who use it. “It is considered to be ‘weight neutral.’ That means it does not cause weight loss or weight gain. However, there are some individuals who experience mild weight loss while on metformin. The data on this varies, but one study found that 29% of people on metformin lost 5% or more of their body weight and just 8% lost around 10% of their body weight.” She also says that while taking the drug, patients experience a slight decrease in appetite and carbohydrate cravings. “By improving insulin resistance, metformin works to make your body make less insulin. That helps with metabolism in a similar way that intermittent fasting or a low-carbohydrate diet can as well,” Dr. Lovig adds.
Will Your Doctor Prescribe Metformin For Weight Loss?
Metformin is specifically for those with type 2 diabetes, or pre-diabetes. If you are overweight, Dr. Griebeler says your doctor may prescribe it as an off-label medication, but it is not FDA-approved as a weight-loss drug. Your doctor may prescribe it to help with managing diabetes, lowering your risk of diabetes or helping with PCOS. But, Dr. Griebeler says metformin can also be prescribed in other instances. “Metformin is a great tool if a patient is taking other medications that can cause weight gain, it will counteract. In addition to that, most patients with type 2 diabetes should be on it, as well as patients with pre-diabetes can slow or stop progression to diabetes if they take metformin.”
What is the Right Metformin Dosage?
Metformin is available in both pill form and liquid. If your doctor prescribes metformin, they will decide on the dosage that’s best for your situation. “The starting dose is 500 mg daily with the max dose being 2400 mg daily,” says Lovig. Most often, doctors start you at a low dosage and gradually increase it over a few weeks to help minimize any side effects.
Could Weight Loss While Taking Metformin Be Caused By Something Else?
If you are losing weight while taking metformin, it could be caused by the medication, or it may not be. Weight loss can be triggered by several other factors. “Metformin is not FDA-approved for weight loss because it doesn’t help the majority of patients lose weight the way other approved medications do. There are newer medications that can help more with weight loss known as ‘GLP agonists,’" Dr. Lovig says. “Commonly known weight loss medications in this class include Saxenda and Wegovy. These medications can be used with metformin.” She says those medications often see more weight loss results than one would with metformin. “They mimic hormones that our stomach makes in the presence of food and have multiple mechanisms of action including supporting insulin production, acting as an appetite suppressant on the brain, and decreasing the transit of food in your stomach which makes you feel fuller longer,” adds Dr. Lovig.
What to Do If You’re Worried About Weight Loss On Metformin
If you are losing weight quickly and have concerns, Dr. Griebeler says you should visit your provider to look for causes of weight loss. Dr. Lovig echoes the sentiment by suggesting you see your doctor to be evaluated, but you can do something in the meantime while waiting for your appointment. “[Patients that] keep a food journal to review with your doctor or medical provider is helpful,” she says. Other conditions and medicines could also cause weight loss, but speaking with your doctor is the best way to find out what’s causing it. Remember, metformin isn’t a miracle drug, and isn’t a substitute for healthy eating and physical activity—it’s primarily used to treat diabetes. So if you are taking it, it’s important to make sure you are following a well-balanced diet and exercising to reap the benefits. Next, find out how to know if you have diabetes.
Sources:
Marcio L Griebeler, MD, Director of the Obesity Center with Cleveland Clinic’s Endocrinology & Metabolism InstituteKay Lovig MD, Section Chief Division of Endocrinology at White Plains HospitalNational Library of Medicine: Long-Term Safety, Tolerability, and Weight Loss Associated With Metformin in the Diabetes Prevention Program Outcomes Study
