Drug Candidate Prevented Muscle Loss During Weight Loss

A study shows a new treatment may help patients preserve muscle mass while taking GLP-1 receptor agonist medications.

Updated on Oct. 14, 2026 in Weight Loss

Bold flat-color editorial illustration of a glass vial, in navy and cream with red, representing pharmaceutical medical research. — Regeneron Pharmaceuticals reported that the drug trevogrumab successfully preserved muscle mass during weight loss in a 52-week clinical trial of participants. AI Illustration. Upload story photo >

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Regeneron Pharmaceuticals has released Phase 2 trial results showing that the drug trevogrumab may prevent muscle loss in people taking weight-loss medication. The 52-week study evaluated the drug in individuals with a BMI of 30 kg/m2 or greater.

Why it matters

While GLP-1 receptor agonists are effective for weight reduction, they can lead to unwanted muscle loss, which potentially impacts long-term metabolic health. This trial explores a way to improve the quality of weight loss by specifically targeting muscle preservation.

In the Phase 2 COURAGE trial, researchers found that trevogrumab prevented 70% of muscle loss compared to placebo in a predefined MRI substudy of adults with a BMI of 30 kg/m2 or greater. The trial assessed participants over a 52-week duration.

The players

Regeneron Pharmaceuticals

A biotechnology company that develops therapies for metabolic, inflammatory, and cardiovascular conditions.

The details

Trevogrumab works by blocking myostatin, a protein that regulates muscle growth, to help preserve lean mass while a person loses weight. During the trial, participants received semaglutide 2.4 mg in combination with the drug for 26 weeks, followed by 26 weeks of trevogrumab alone or a placebo. Researchers monitored for adverse events, which included nausea, vomiting, constipation, and diarrhea.

October 01, 2026: Regeneron Pharmaceuticals released Phase 2 trial results.
26 weeks: Duration of the initial combination treatment phase.
52 weeks: Full duration of the COURAGE trial.

Health Landscape

This development reflects a shift in metabolic research toward improving the body composition outcomes of pharmaceutical weight-loss treatments. The COURAGE trial signals a growing focus on addressing muscle wasting as a side effect of systemic weight reduction.

If you are using GLP-1 receptor agonists and are concerned about muscle mass, monitor for common side effects like nausea or vomiting. The effectiveness of muscle-preserving agents is an evolving area of science worth discussing with your doctor as new clinical data becomes available.

The takeaway

Preserving muscle mass during weight loss is a key priority for maintaining long-term metabolic health. Track your activity levels and consult your physician about your nutrition and resistance training plan if you are taking weight-loss medications.