The Medical Advisor

Updated October 2, 2026 Semaglutide and tirzepatide can produce substantial weight loss, but an important question has emerged alongside the popularity of GLP-1-based obesity medicines: How much of the weight lost is fat, and how much is lean mass? The question is more complicated than it first appears. Studies of semaglutide and tirzepatide show that both drugs reduce fat mass and also reduce lean mass during weight loss. However, lean mass is not synonymous with skeletal muscle , and results from separate trials cannot be interpreted as a direct head-to-head comparison of muscle preservation. A 2026 systematic review and meta-analysis of 20 randomized controlled trials involving 15,782 participants estimated that lean mass accounted for approximately 35.2% of weight lost with semaglutide and 25.4% with tirzepatide . However, the authors did not establish that tirzepatide preserves functional skeletal muscle better than semaglutide. The analysis also found that ad...

GLP-1-based medications have changed the treatment of obesity by making substantial, sustained weight loss possible for many people. But as these medicines become more widely used, another question has become increasingly important: How much of the weight lost on a GLP-1 drug comes from muscle or other lean tissue—and can that loss be minimized? The evidence shows a nuanced answer. People taking semaglutide, tirzepatide and related incretin-based medicines generally lose much more fat than lean tissue . At the same time, absolute lean mass usually falls during substantial weight loss. Importantly, lean mass is not the same thing as skeletal muscle : DXA-based “lean mass” also includes water, organs and other non-fat tissues. Therefore, a finding that lean mass decreased does not automatically mean that the same amount of skeletal muscle was lost. Recent 2026 meta-analyses suggest that roughly one-quarter to one-third of total weight lost with incretin therapy may be classified as lean ...

OneDayMD Evidence Guide • Updated October 2026 Dimethyl sulfoxide (DMSO) is an unusual compound: a powerful solvent, a membrane-penetration enhancer and a substance with genuine clinical applications. It is also surrounded by exaggerated claims. This guide separates established medicine from promising research, anecdotes and unsupported “miracle cure” narratives. Evidence focus: topical DMSO, interstitial cystitis, pain, penetration enhancement, safety, drug interactions, cancer research, amyloidosis and common online claims. Important:  The fact that DMSO penetrates biological membranes does not mean it makes any substance placed on the skin safe or effective. Because DMSO can enhance penetration, contaminated skin or inappropriate mixtures may increase exposure to other chemicals or drugs. What Is DMSO? Dimethyl sulfoxide (DMSO) is a sulfur-containing organic compound with the chemical formula C 2 H 6 OS. It is a clear liquid that mixes readily with water...