Saving muscle while losing weight: A vital strategy for sustainable results while on glucagon-like peptide-1 related drugs.
This review paper examines the challenge of preserving muscle mass during weight loss induced by GLP-1–based pharmacotherapies, including GLP-1 receptor agonists (e.g., semaglutide), dual GLP-1/GIP agonists (e.g., tirzepatide), and triple GLP-1/GIP/glucagon agonists (e.g., retatrutide). The authors note that while these agents can produce clinically meaningful weight loss (5–10% or more of body weight), a portion of that loss comes from lean mass, including skeletal muscle, which may contribute to long-term weight regain and increase the risk of sarcopenia. The paper discusses the biology of myokines—over 600 signaling proteins released during muscle contraction identified in human myocyte research—as potentially important targets for protecting or expanding muscle mass. The authors explore emerging anti-obesity agents and their potential combinations with incretin-based therapies to preferentially reduce fat mass while sparing or building muscle. The paper calls for further research to clarify the functional consequences of lean mass changes during weight loss and maintenance. As a narrative review, it synthesizes existing literature without conducting original trials, and no new clinical data are presented. Generalizability is limited by the review format and the evolving evidence base for newer agents.
Why this grade: This is a narrative review synthesizing existing literature on GLP-1–related therapies and muscle preservation; it presents no original clinical trial data and thus provides indirect, synthesized evidence rather than direct experimental findings.
Obesity affects over 1 billion people worldwide and is linked to more than 230 health complications, with cardiovascular disease being a leading cause of mortality. Losing 5%-10% of body weight is considered clinically significant for improving health. This weight loss can be achieved through pharmacotherapy, including glucagon-like peptide 1 (GLP-1) receptor agonists, GLP-1/glucose-dependent insulinotropic peptide dual receptor agonists, and GLP-1/glucose-dependent insulinotropic peptide/glucagon triple receptor agonists (such as semaglutide, tirzepatide, and retatrutide, respectively). While much of the weight loss comes from fat mass, these treatments also result in the loss of lean mass, including muscle. This loss of muscle may contribute to difficulties in maintaining weight over the long term and can lead to sarcopenia. Therefore, the focus of new anti-obesity treatments should be primarily on reducing fat mass while minimizing the loss of muscle mass, ideally promoting muscle gain. Research focusing on human myocytes has identified more than 600 myokines associated with muscle contraction, which may play a crucial role in preserving both muscle mass and function. We explored the potential of new anti-obesity agents and their combinations with incretin-based therapies to achieve these outcomes. Further studies are needed to better understand the functional implications of lean mass expansion during weight loss and weight maintenance programs.
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