Research

Energy balance

Current pharmacological treatments for obesity, including incretin-based therapies (semaglutide, tirzepatide), result in significant skeletal muscle loss (approx. 7-10% of lean mass) alongside fat loss.

If you are using GLP-1 medications, expect to lose some muscle. You must actively combat this by eating enough protein and doing resistance training to preserve your metabolic engine.

StrongSupportsHIGH confidence
Semaglutide (2.4 mg/week) and tirzepatide (5, 10, and 15 mg/week)... were associated with net losses of 10.1% and 7.9% of initial lean mass over the 68- to 72-week treatment periods.
Mary‐Ellen Harper et al. · Diabetes · 2025

Why this rating

Cites specific large-scale clinical trials (STEP 1, SURMOUNT-1).

Source

High-Quality Weight Loss in Obesity: Importance of Skeletal Muscle

Mary‐Ellen Harper et al. · Diabetes · 2025

DOI 10.2337/dbi25-0003

narrative_reviewCited 13×
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DOI resolved against Crossref · corpus check 2026-06-10

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