GLP-1 receptor agonists like semaglutide and tirzepatide reduced adipose-derived stem cells in subcutaneous tissue by approximately 75% compared to controls (11.0 vs 44.8 cells/mm²). This depletion occurred selectively in stem cell populations while leaving fibroblast counts unchanged, suggesting a targeted biological effect rather than general tissue degradation. The finding provides the first direct mechanistic evidence for why millions of people taking these blockbuster weight-loss drugs report premature facial aging, skin laxity, and volume loss beyond what weight reduction alone would explain. This represents a significant safety consideration for long-term GLP-1 use, as adipose-derived stem cells play crucial roles in skin repair, collagen production, and maintaining facial volume. The study's small sample size of 10 patients limits generalizability, and the cross-sectional design cannot establish causation or reversibility. However, the magnitude of stem cell reduction is striking and warrants immediate larger-scale investigation. For the estimated 15 million Americans on GLP-1 therapy, this finding suggests the need for proactive skin health monitoring and potential adjunctive treatments to preserve dermal integrity during extended use.