# Trial Tests Muscle Sparing Antibodies Alongside Semaglutide

> A phase 2 trial called COURAGE tests antibodies against GDF8 and activin A to protect muscle during semaglutide weight loss.

- URL: https://www.lifeconverted.com/learn/trial-tests-muscle-sparing-antibodies-alongside-semaglutide
- Category: Research News
- Author: Jonas Berg, Metabolic Health Writer
- Published: 2026-11-12
- Reading time: 1 min
- Keywords: Trial Tests Muscle Sparing Antibodies Alongside Semaglutide

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A new phase 2 trial, described in [a Lancet study indexed on PubMed](https://pubmed.ncbi.nlm.nih.gov/43014326/), looked at whether blocking specific growth factor signals can preserve muscle mass in people losing weight on [semaglutide](/peptides/semaglutide). The trial, named COURAGE, was a two part, randomized, double blind, placebo controlled study in people with obesity.

Participants received trevogrumab, an antibody targeting GDF8, the signaling protein also known as myostatin, either alone or combined with garetosmab, an antibody against activin A. Myostatin and activin A are both part of the same signaling family that normally limits muscle growth, so inhibiting them is one strategy researchers are exploring to counter the lean mass loss that often accompanies rapid weight reduction on GLP-1 class medications. Readers interested in how myostatin blocking is approached in research settings can see background on [myostatin inhibitors](/peptides/myostatin-inhibitor).

This is early stage clinical research, not an approved treatment approach, and the combination of an antibody therapy with an approved weight loss medication like semaglutide represents an investigational strategy still being tested for safety and effectiveness. Trevogrumab and garetosmab are not peptides and are not available as research compounds, but the underlying biology connects to ongoing interest in myostatin pathway modulation across metabolic and muscle research.

*This article is for education only. It is not medical advice. Compounds discussed here are sold for research purposes. Talk to a licensed clinician before making health decisions.*

## Sources

- Lancet, 2026, via PubMed: https://pubmed.ncbi.nlm.nih.gov/43014326/

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