Hair Sciences: The Hair Cycle Discussed with Dr. Gilliam Westgate

In 2009, Dr. Gill Westgate discussed the hair cycle, emphasizing the shedding phase and the role of androgens in hair growth. The hair follicle goes through cyclical changes, transitioning through anagen, catagen, and telogen stages. Androgens, which transform hair growth during puberty and contribute to pattern baldness, were found to affect insulin-like growth factor 1 (IGF1), Dickkopf-1 (DKK1), and transforming growth factor beta (TGF-beta). These factors were found to inhibit proliferation in the anagen hair follicle bulb matrix, suggesting that anagen VI is the target state of the follicle for androgen action. The severity of balding was influenced by both genetic and non-genetic factors. The study also recognized exogen as a distinct phase of the hair growth cycle, defined by the time between the formation of a telogen club hair and its eventual expulsion from the follicle. The study concluded that understanding the role of shedding within the normal hair cycle and its relationship with the length of anagen could help reduce concerns about hair shedding.