Greying and Beauty: Biology, Semiotics, and Aesthetics of Age Metamorphosis Introduction: Greying as a Biochemical and Cultural Phenomenon Greying of hair is a complex biological process that historically carried a powerful symbolic load, different from the modern aesthetic evaluation. While traditionally greying was associated with aging, today it is increasingly reinterpreted as a sign of maturity, naturalness, and conscious elegance. This shift requires an interdisciplinary analysis, uniting data from molecular biology, perception psychology, and sociocultural studies. 1. Biochemistry of Greying: Why Hair Loses Color The color of hair is determined by the presence and ratio of two types of melanin — eumelanin (black-brown pigment) and pheomelanin (yellow-red). Their synthesis occurs in specialized cells — melanocytes, located in the hair follicle. The process of greying involves several key mechanisms: Exhaustion of the stem cell pool of melanocytes (SCM). With each cycle of hair growth (anagen), the pool of SCM decreases. When it is depleted, new melanocytes are not formed. Oxidative stress and accumulation of hydrogen peroxide (H₂O₂). With age, the activity of the enzyme catalase, which breaks down H₂O₂, decreases in the hair follicle. Its excess blocks the synthesis of tyrosinase — a key enzyme in melanin production. Genetic predisposition. Genes such as IRF4, PRSS53, affect the time of onset and speed of greying. This determines 70-80% of when a person will go grey. Lifestyle factors. Chronic stress, according to some data, may accelerate greying through its effect on the sympathetic nervous system, which exhausts stem cells of melanocytes. Deficiency of vitamin B12, copper, iron also plays a role. Interesting fact: A study published in Nature in 2021 showed that greying caused by acute stress can be reversible. Scientists linked individual grey hairs to periods of stress in the lives of participants and found that with a decrease in stress load, t ... Read more