TLDR Androgens affect hair growth and shedding, with genetic and non-genetic factors influencing baldness.
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.
81 citations,
April 2009 in “Journal of Investigative Dermatology” Hair shedding is an active process that could be targeted to treat hair loss.
171 citations,
July 2007 in “Journal of Investigative Dermatology” A substance called DKK-1 increases in balding areas and causes hair cells to die when exposed to DHT.
829 citations,
May 2007 in “Nature” Hair follicles can regrow in wounded adult mouse skin using a process like embryo development.
35 citations,
March 2007 in “Skin Research and Technology” The conclusion is that exogen is a unique hair cycle phase and the new sampling method specifically targets this stage, which may help in future hair loss research.
227 citations,
January 1998 in “Journal of Endocrinology” Cells from balding scalps have more androgen receptors than cells from non-balding scalps.
416 citations,
September 1997 in “Journal of Investigative Dermatology” People with hair loss have more androgen receptors and enzymes in certain follicles, with men and women showing different patterns.
173 citations,
July 1995 in “Biochemical and biophysical research communications” Male hormones promote hair cell growth by using a growth factor from nearby skin cells.
67 citations,
July 1985 in “British journal of dermatology/British journal of dermatology, Supplement” Men's thigh hair grows longer and has a longer growth cycle than women's, but arm hair growth is similar between genders.
3 citations,
June 2006 in “Expert Review of Dermatology” The document concludes that hair loss is complex, affects many people, has limited treatments, and requires more research on its causes and psychological impact.
10 citations,
January 2009 in “Elsevier eBooks” Hair growth is influenced by hormones and goes through different phases; androgens can both promote and inhibit hair growth depending on the body area.
51 citations,
January 2003 in “Hormone Research in Paediatrics” Hormones and their receptors, especially androgens, play a key role in hair growth and disorders like baldness.
102 citations,
July 2020 in “International journal of molecular sciences” Hormones like testosterone and estrogen significantly affect hair growth and structure.
209 citations,
September 2008 in “Dermatologic Therapy” Androgens can both increase and decrease hair growth in different parts of the body.
