Blocking the activin type II receptor to protect muscle during weight loss

Role of Activin Type II Receptor Signaling in Muscle Hypertrophy, Obesity, and Weight Loss

NIH-funded research University of Pennsylvania · NIH-11238449

This research looks at whether adding an activin type II receptor blocker can help people using GLP‑1 weight‑loss medicines lose fat while keeping or gaining muscle.

Quick facts

Grant typeR01 grant
Study typeNIH-funded research
Funding institutionUniversity of Pennsylvania NIH-funded
Lab location1 site (Philadelphia, United States)
Project IDNIH-11238449 on NIH RePORTER

What this research studies

This project tests combining activin type II receptor blockade with commonly used GLP‑1 weight‑loss drugs to try to preserve or increase skeletal muscle while reducing fat. Researchers will use animal experiments and build on early human data to study body composition, muscle strength, and metabolic measures during combined treatment. The team will measure how the combination affects energy expenditure, fat regain after stopping therapy, and the biological pathways that control muscle and fat. The goal is to find approaches that give higher‑quality weight loss—more fat loss with less muscle loss—to improve long‑term health and function.

Who could benefit from this research

Good fit: Adults with obesity who are considering or already taking GLP‑1 based weight‑loss medications and who are concerned about losing muscle during weight loss would be the main candidates.

Not a fit: People without obesity, not using GLP‑1 drugs, or whose muscle problems are caused by unrelated neuromuscular diseases may not benefit from this approach.

Why it matters

Potential benefit: If successful, this approach could let people on GLP‑1 medications lose mostly fat while preserving or increasing muscle, lowering the risk of weight regain and loss of strength.

How similar studies have performed: Previous trials of ActRII blockers like bimagrumab have increased muscle mass and reduced fat in humans, but combining ActRII blockade with GLP‑1 therapies is a newer concept with limited clinical testing so far.

Where this research is happening

Philadelphia, United States

Researchers

About this research

  1. This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
  2. Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
  3. For full project details, budget, and progress reports, visit the official NIH RePORTER page below.
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.