Stress Inhibits Hair Growth in Mice by Induction of Premature Catagen Development and Deleterious Perifollicular Inflammatory Events via Neuropeptide Substance P-Dependent Pathways

The study from March 2003 investigated the effects of stress on hair growth in mice, finding that stress caused premature termination of the hair growth phase and induced harmful inflammatory events around hair follicles through a pathway mediated by the neuropeptide substance P. Stress increased apoptosis and decreased proliferation in hair follicles, leading to premature catagen development, which could be replicated by administering substance P to non-stressed mice and mitigated by using a substance P receptor antagonist in stressed mice. The study involved at least 10 microscopic fields each of four to five different mice, with a minimum of 30 different hair follicles per mouse, although the exact number of mice used was not specified in the summary. The findings suggest a potential treatment for stress-induced hair loss in humans using substance P receptor antagonists.