In muscle cells grown from older adults, semaglutide and GIP did not directly shrink the fibers

What the research found

Caitlin Ditchfield and colleagues reported in GeroScience on 4 November 2026. They grew primary muscle cells from skeletal muscle of older adults with obesity who were having orthopaedic surgery. GIP receptor messenger RNA was present in every donor. GLP-1 receptor messenger RNA was not detected by PCR. In a subset of three donors, a fluorescent probe found low-level GLP-1 receptor protein on the surface of 51 to 66 percent of the immature muscle cells. Differentiated muscle fibers were treated with semaglutide or with GIP peptide. Neither treatment changed atrophy-related gene expression or the measured secretome. Semaglutide lowered glycolytic and total ATP production and lowered lactate release. Mitochondrial measures did not change. Neither treatment thinned the fibers or blocked differentiation. After 8 days, GIP increased fiber thickness. The authors read this as consistent with an indirect explanation for the lean-mass loss seen with incretin drugs in people, such as eating less and loading the muscle less. This is a cell study. It did not measure strength, falls, or weight in people. Semaglutide is a prescribed medicine. DOI 10.1007/s11357-026-02625-w. Not medical advice.

Evidence level: Animal study. Results in animals or cells often don't carry over to people.

Not medical advice. Not a substitute for a prescribed medicine. Off-label prescription use is clinician-only. VitaLonga does not diagnose, treat, or cure disease. Never start, stop, or replace a prescription with a supplement on the basis of a headline.

Read the original at GeroScience