A recent study suggests that certain weight loss drugs, while effective at reducing body weight, may negatively impact skeletal muscle health. The findings, published in The Lancet, emphasize that weight loss medications, particularly GLP-1 receptor agonists found in drugs like Ozempic, Wegovy, Mounjaro, and Zepbound, could lead to considerable muscle loss over time. Though these drugs have proven beneficial for obesity treatment—a key preventive measure against diseases like diabetes, hypertension, and cancer—the study warns that they may simultaneously contribute to the decline of muscle mass.
GLP-1 receptors, which play a role in managing blood sugar by promoting insulin secretion and controlling appetite, are targeted by these drugs to aid in blood glucose regulation and weight management. However, researchers from Pennington Biomedical Research Center in the US and Canadian institutions like the Universities of Alberta and McMaster caution that muscle loss can represent a substantial percentage—about 25 to 39%—of the total weight lost during 36 to 72 weeks of treatment.
The decline in skeletal muscle, they argue, is significant because it not only weakens physical strength but also disrupts metabolic health and immune function. In fact, muscle loss induced by these medications is reportedly more pronounced than what would result from standard dieting or the natural aging process. This decline could worsen sarcopenic obesity—a condition marked by both excess fat and reduced muscle—linked to cardiovascular disease and higher mortality rates.
Steven Heymsfield, a professor of metabolism and body composition at Pennington, advises patients considering these drugs to stay mindful of potential side effects, noting that reduced appetite may lead to inadequate intake of essential vitamins and minerals. To counterbalance these risks, the researchers recommend that patients pair these medications with a diet rich in protein and regular exercise, potentially mitigating the adverse impact on muscle health.
