What Do We Know About Hair Growth Induced by Wounding and Its Therapeutic Applications?

The article explores the relationship between wound healing and hair follicle growth, and the potential of wound-induced procedures to stimulate hair growth. Hair growth after wounding in humans is thought to be due to the activation of existing hair follicles, changes in the hair cycle, or activation of signaling pathways that increase hair follicle proliferation and hair shaft thickening. The article reviews the use of microneedling, fractional laser, and scalp threading as hair growth therapies for male androgenetic alopecia and female pattern hair loss. The largest study mentioned involved 117 patients with a history of bone fractures, with 34.2% reporting localized hypertrichosis (excessive hair growth). However, the efficacy and safety of these procedures as treatments for androgenetic alopecia are not yet fully established due to a lack of high-quality evidence. The article concludes that further randomized controlled studies with larger patient numbers and more appropriate objective outcome measurements are needed.