Aging and Anti-Aging in Hair and Hair Loss

Aging is an accelerating and escalating phenomenon and reality worldwide. According to the World Health Organization, over 2 billion people will be aged 60 years and older by 2050. Aging changes every aspect of human life and influences all medical disciplines. Geriatrics and gerontology are gaining growing significance in daily practice. The pathogenesis of hair aging remains largely unknown and is now under intensive investigation. Progeria/progeroid syndromes or silver/white hair syndromes are good natural models for the study of hair aging in vivo. Aging appears to exert no effect on the number, expression, and distribution of hair follicle stem cell markers, although melanocyte stem cells are obviously affected. Chronic persistent low-grade inflammation is an essential hallmark of the aging process, so-called inflammaging, while ultraviolet irradiation, skin microbes, and stress are among the most important etiologies for inducing a proinflammatory state in skin and hair follicles. Inflammation also plays a crucial role in the pathogenesis of different hair diseases, especially alopecia areata, folliculitis decalvans, lichen planopilaris, and telogen effluvium. Antioxidants, phytoestrogens, and retinoids have been demonstrated to possess anti-aging effects on hair follicles. Antioxidation takes center stage in current anti-aging strategies, in which polyphenols are the most extensively studied and promising agents. There is preliminary evidence for beneficial effects of certain nutraceuticals such as trace elements and polyamines in the anti-aging of hair. However, the optimal dosage and application route remains to be determined. Further extensive well-controlled clinical studies are required to confirm the effects of antioxidants in the prevention, interruption, and reversal of hair aging.