Study Shows Experimental Drug Could Preserve Muscle Mass in GLP-1 Weight-Loss Users

Researchers testing an experimental antibody medication called apitegromab alongside the weight-loss drug tirzepatide found that patients who received both treatments retained significantly more muscle mass than those receiving tirzepatide alone. In a 24-week clinical trial involving 102 overweight or obese participants, both groups lost roughly equivalent amounts of weight, but the apitegromab group retained around 55% more lean mass and showed slightly greater grip strength and leg strength performance. GLP-1 medications like Ozempic, Wegovy, and Zepbound have become increasingly popular, with approximately one in eight US adults now using them, but research indicates that 25-40% of weight loss from these drugs comes from muscle rather than fat. Apitegromab works by blocking myostatin, a protein that contributes to muscle breakdown, though it has not yet been approved by the FDA and is currently available only through intravenous infusions. Researchers are calling for additional studies to explore whether the drug could help address sarcopenia, the age-related loss of muscle mass and strength that increases fall risk and loss of independence.