Health knowledge and news provided by doctors.

How Effective Are Prescription Weight Loss Drugs?

prescription weight loss drugs

JAMA just published the results of an analysis of five prescription weight loss drugs when compared with placebo, and the findings may surprise you. Just how effective are prescription weight loss drugs and should you and your doctor consider them?


The five weight loss drugs studied (liraglutide [Saxenda], lorcaserin [Belviq], naltrexone/bupropion [Contrave], orlistat [Alli], and phentermine/topiramate [Adipex-P]) are all for use in individuals who are obese or, if overweight, have at least one weight-associated condition, such as high cholesterol, high blood pressure, or type 2 diabetes. Until now, little information has been published regarding their comparative effectiveness.

Prescription weight loss drug study

A total of 28 randomized clinical trials involving 29,018 individuals were evaluated. The median body weight at baseline was 222 pounds and 74 percent of the participants were women.

These prescription weight loss drugs are considered to be effective if an individual loses at least 5 percent of their starting body weight. A 5 percent drop in weight has been identified as lowering the risk of heart disease and type 2 diabetes.

In this review and meta-analysis, the authors found the following:

23 percent of participants who took a placebo lost at least 5 percent of their body weight compared with:

  • 75 percent of those taking phentermine-topiramate
  • 63 percent who took liraglutide
  • 55 percent who took naltrexone-bupriopion
  • 49 percent who took lorcaserin
  • 44 percent who took orlistat

Follow eMaxHealth on YouTube, Twitter and Facebook.
Please, click to subscribe to our Youtube Channel to be notified about upcoming health and food tips.

After one year of using the various weight loss drugs (along with a reduced calorie diet and exercise, which is always recommended when people are prescribed these drugs), the average weight loss per drug was:

  • Phentermine-topiramate, 19.4 lbs
  • Liraglutide, 11.7 lbs
  • Naltrexone-bupropion, 11 lbs
  • Lorcaserin, 7.1 lbs
  • Orlistat, 5.7 lbs

When it came to study participants who chose to stop using a weight loss drug because of side effects, both liraglutide and naltrexone-bupropion had the most dropouts compared with placebo.

Are prescription weight loss drugs effective?

The findings of this meta-analysis suggest that phentermine-topiramate is the most effective of the prescription weight loss drugs. This drug is a combination of an appetite suppressant (phentermine, similar to an amphetamine) and an antiseizure medication (topiramate).

The difference in weight loss between the seemingly most effective weight loss drug and the other four is considerable, from nearly two times to more than three times less pounds lost. However, that does not mean everyone can expect to reap the same results, nor that even using a prescription weight loss drug is appropriate for individuals who fit the criteria. Some individuals may consider the weight loss possible when using a few of these drugs not to be worth the risk of experiencing side effects.

According to the study’s authors, “the ideal approach to weight loss should be highly individualized, identifying appropriate candidates for pharmacotherapy, behavioral interventions, and surgical interventions.” That’s something to consider if you are obese or seriously overweight.

Khera R et al. Association of pharmacological treatments for obesity with weight loss and adverse events: a systematic review and meta-analysis. JAMA 2016; 315(22): 2424-34

Image courtesy of Pixabay