Muscle loss on GLP-1s

Find out how much muscle people really lose on GLP-1 drugs and what protects it. Each guide names the trial, how many people it measured and how.

• Does Mounjaro or Zepbound cause muscle loss? What the SURMOUNT-1 scans showed

  Tirzepatide (Mounjaro, Zepbound) lowers lean mass along with fat, as large weight loss commonly does. In the SURMOUNT-1 body-scan substudy (n = 160, DXA, 72 weeks), about 26% of the weight lost was lean mass, and lean mass includes water and organs, not only muscle. Protein and strength training are the levers that protect it.

• Does Ozempic cause muscle loss? What the STEP 1 scans showed

  Semaglutide lowers lean mass along with fat, as any large weight loss does. In the STEP 1 body-scan substudy (n = 140, DXA), lean mass made up about 40% of the tissue lost, though lean mass includes water and organs, not only muscle. Strength training and enough protein are the levers that protect it.

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