Ref 34
Know Your Numbers
Hype watch
Protecting muscle on GLP-1s - IBIO-610 primate data
14th October 2026
iBio reported an eight-week study in obese nonhuman primates combining its investigational antibody IBIO-610 with semaglutide. In the combination group, lean mass made up about 6 percent of total weight lost, versus about 22 percent with semaglutide alone, and fat accounted for a larger share of the loss.
Key takeaways:
- Muscle loss is the known cost of GLP-1 weight loss; preserving lean mass is directly relevant to strength, frailty risk and long-term metabolic health
- A single IBIO-610 dose cut a target protein marker (active Activin E) by a reported 97 percent at week 8 in primates, with a long half-life that the company projects could allow infrequent dosing in humans
- There are no human data yet: first-in-human trials are planned for the first half of 2027
Hype check: Proven - nothing in humans. Promising - a clear body-composition signal in a small primate study (6 animals per group), company-reported. Marketing - any framing of this as a proven companion therapy for people on GLP-1s; that test has not started.
Why it matters - As GLP-1 use scales, the quality of weight loss - fat versus muscle - becomes a central healthspan question, especially for older users. This is an early candidate answer, tracked here at the animal-data stage so later human results can be judged against it.