Research
Hormonal
Greater lean body mass loss with tirzepatide is mechanistically linked to its dual GLP-1/GIP receptor agonism, as GIP receptors are broadly expressed in immune, stromal, and vascular muscle compartments, unlike the more restricted GLP-1 receptor.
Tirzepatide's unique ability to activate GIP receptors may affect muscle tissue differently than semaglutide by influencing immune and vascular cells in muscle, potentially contributing to greater muscle loss.
ModerateSupportsMEDIUM confidence
An independent analysis of all available Single-cell RNA-seq data from human musculature showed broader GIPR+ cellular distribution than GLP1R+ cells across immune, stromal, vascular, and contractile compartments, providing plausible biological context for the greater LBM loss observed in routine care with tirzepatide (dual GLP1R-GIPR agonist) relative to semaglutide (GLP1R-specific agonist).
Why this rating
Based on single-cell RNA-seq data, which is hypothesis-generating and does not establish causal mechanism in vivo.
Source
Greater lean-body-mass decline with tirzepatide than semaglutide in routine care, revealed by body-composition digital phenotyping
Karthik Murugadoss et al. · medRxiv · 2026
DOI 10.64898/2026.04.11.26350687
preprint · n=670422
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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