The Most Effective Drugs for Weight Loss

You may be able to drop pounds with FDA-approved prescription medications.

Medically reviewed in January 2022

Does taking weight-loss medication actually help you drop pounds? And if so, which one might work best for you? 

For a study published in JAMA in 2016, researchers analyzed the effects of five weight-loss drugs approved by the U.S. Food and Drug Administration (FDA). Over the course of 52 weeks, each medication was associated with at least a 5 percent drop in pounds—and some worked better than others. 

The problem

Globally, 1.9 billion adults are overweight, according to the World Health Organization (WHO). Based on body mass index (BMI), about 650 million of these people are considered to be obese. BMI is an estimate of the amount of fat in your body derived from your height and weight. A person with a BMI of greater than or equal to 25 is deemed to be overweight. An obese person has a BMI greater than or equal to 30. 

There are numerous health risks associated with being overweight or obese, including type 2 diabetes and hypertension. Dropping between 5 and 10 percent of your body weight can improve your blood pressure, blood sugar and cholesterol levels—and lower your chances of many of the complications linked to excess weight. 

The study set-up

For the JAMA study, scientists looked at data from 28 randomized clinical trials involving more than 29,000 overweight and obese adult patients. Each patient had been treated with an FDA-approved long-term weight loss medication for at least one year.

The medications were approved for obese patients or for those with a BMI greater than or equal to 27 who had at least one weight-related health condition. Such conditions included type 2 diabetes, hypertension and high cholesterol.

The results

Of the patients in the JAMA study who took a placebo, 23 percent experienced at least a 5 percent weight loss. Those who took a prescription drug all had higher rates of success.

The medications phentermine-topiramate (Osymia), liraglutide (Saxenda), naltrexone-bupropion (Contrave) and locaserin (Belviq) are designed to decrease appetite and increase fullness. In the study, about 75 percent of phentermine-topiramate users experienced at least a 5 percent drop in body weight, compared to 63 percent of liraglutide users, 55 percent of naltrexone-bupropion users and 49 percent of locaserin users. 

The fifth medication, orlistat (Xenical), blocks fat absorption. In the study, 44 percent of orlistat patients experienced at least a 5 percent weight loss—for an average of 5.7 pounds lost within a year.     

Would weight-loss medication work for you?

Before taking any weight loss medication, you should always consult with your healthcare provider (HCP), as dropping pounds should be a highly individualized process. Your HCP can assess your health condition, recommend lifestyle changes and prescribe drugs if it’s the right choice for you. They can also advise you of any weight-loss medication side effects, which may include headache, nausea, dry mouth, increased blood pressure and constipation.

To note: Belviq, one of the five medications in the study, is no longer available in the U.S. The FDA raised concerns about the drug in February 2020 because it was linked to an increased cancer occurrence during trials. The manufacturer, Eisai, agreed to pull it from shelves.

Article sources open article sources

R Khera, MH Murad, et al. “Association of Pharmacological Treatments for Obesity With Weight Loss and Adverse Events: A Systematic Review and Meta-analysis.” JAMA. 2016 Sep 6;316(9):995. 
World Health Organization. “Obesity and Overweight.”
Centers for Disease Control and Prevention. “About Adult BMI,” “Losing Weight.”
Harvard Health Publishing. “Controlling your weight is key to lowering stroke risk.”
U.S. Food and Drug Administration. “Belviq, Belviq XR (lorcaserin) by Eisai: Drug Safety Communication - FDA Requests Withdrawal of Weight-Loss Drug.”
Adam Feuerstein. “Weight-loss drug to be pulled from market after FDA expresses concerns on cancer risk.” STAT. February 13, 2020.

More On

What are some simple ways for me to cut calories?


What are some simple ways for me to cut calories?
You can cut calories by as much as 22 percent without changing your diet at all, says nutritionist Kate Geagan. Watch the video to learn more about th...
6 Ways to Eat More Mindfully


6 Ways to Eat More Mindfully
If dinner feels like a race against the clock, then consider this a speeding ticket from the food police. Quickly plowing through your meals until yo...
Everything You Ever Wanted to Know About the Flexitarian Diet


Everything You Ever Wanted to Know About the Flexitarian Diet
The top 13 takeaways from this plant-based eating plan.
Quick weight loss tip


Quick weight loss tip
Looking for a quick and easy way to lose weight? Watch this video to learn a helpful but simple weight loss tip from Dr. Robin Miller.
Surprising calorie shockers


Surprising calorie shockers
Eating out means navigating a mine field of hidden calories, fat, and sodium. In this Health Smarts video, Robin Miller, MD, spotlights "healthy" calo...