SHH and Obesity: Obesity-related metabolic stress induces premature entry into the anagen phase and disrupts the balance of the hair cycle, leading to accelerated hair thinning and loss.26, 28 Various pathways, including inflammatory cytokine signaling and oxidative stress, can contribute to hair aging due to obesity; for example, inflammatory signals like Interleukin-1β (IL-1β) inhibit Shh signaling in HF stem cells, further exacerbating hair loss.26