Getting Under the Skin of Hair Aging: The Impact of the Hair Follicle Environment

The review article from July 1, 2020, examines the effects of the aging scalp environment on hair follicles and hair aging, noting that changes in hair characteristics such as diameter, lustre, and texture occur with age, and that hair loss is common in both genders, with men experiencing pattern balding and women showing diffuse thinning. The document emphasizes the importance of the dermal environment in hair follicle function and suggests that aging-related changes in scalp skin contribute to hair aging. It discusses the role of estrogens in hair follicle biology, indicating that they can extend the growth phase and delay hair shedding, with variations based on gender and age. The review also addresses the impact of hypoestrogenism on female pattern hair loss, the expression of estrogen receptors in hair follicles, and the influence of aging on estrogen synthesis. Additionally, it highlights the need for more research to understand the complex interactions between the scalp environment and hair follicle aging, including the effects of structural changes, inflammation, oxidative stress, and mitochondrial dysfunction in aging skin, as well as the reduction in subcutaneous white adipose tissue thickness. The document concludes that a deeper understanding of these factors is crucial for developing effective treatments for hair loss and skin aging.