IGF1 and hydrops fetalis: In an organ-cultured human scalp HF and cultured human ORS keratinocytes, TRPV1-specific stimulation by capsaicin inhibited hair shaft elongation, suppressed proliferation, enhanced apoptosis, led to premature catagen, upregulated hair growth inhibitors (IL-1β and transforming growth factor-β2) and downregulated hair growth promoters (hepatocyte growth factor, insulin-like growth factor-I (IGF-I), and stem cell factor) [106].