FRIDAY, April 17, 2026 (HealthDay News) -- In many incretin-based interventions, reductions in muscle-related indices exceed prespecified benchmarks, according to a review published online April 17 in the Annals of Internal Medicine to coincide with the Internal Medicine Meeting, the annual meeting of the American College of Physicians, held from April 16 to 18 in San Francisco.
John A. Batsis, M.D., from the University of North Carolina at Chapel Hill School of Medicine, and colleagues examined body composition changes associated with incretin therapies (of interest were liraglutide, semaglutide, tirzepatide, and dulaglutide) in adults with obesity in a systematic review including 36 studies (median of 71 participants).
The researchers found that weight loss was consistently larger in the incretin intervention versus the placebo or lifestyle intervention comparator groups and was accompanied by a decrease in total fat mass and visceral adiposity. There was wide variation in the degree of muscle-based losses. Across agents and measurement methods within the incretin groups, the median proportion of total weight loss attributable to reductions in muscle-based indices was 34.9 percent; 68 percent of studies exceeded the benchmark of about 25 percent. The median was about 34.9 percent of total weight loss in studies using bioelectrical impedance analysis or dual-energy X-ray absorptiometry, with 65 percent exceeding the 25 percent benchmark; the median was about 35.8 percent in studies using computed tomography or magnetic resonance imaging, with all studies exceeding the 15 percent benchmark. The 14 studies reporting weight loss in the lifestyle or placebo comparator groups accounted for −2.4 percent median weight loss, 50 percent of which exceeded the respective benchmark.
"Although current and emerging therapies demonstrate promising efficacy, their pleiotropic effects on body composition extend beyond fat reduction and require careful study," the authors write.