Grey hair usually appears between ages 30 and 40 as follicle cells stop producing melanin, trichologists Sheila Bellotti and Regina Carralero explained.
While greying is a natural part of the aging process within the hair follicles, genetic inheritance, lifestyle factors, and specific health conditions also determine when a person loses hair color.
Hair color is determined by melanin, a biological pigment produced by specialized cells called melanocytes located at the base of each hair follicle. During every new growth cycle, these melanocytes transfer melanin into the growing strand, giving hair its natural shade of black, brown, blonde, or red.
As the body ages, melanocytes become less efficient and gradually reduce their melanin output until production ceases completely. New hair strands then grow without pigment, resulting in a white or grey appearance. At the same time, the body's reservoir of stem cells responsible for renewing melanocytes over a lifetime gradually depletes, leaving follicles unable to generate pigmented hair.
Role of Genetics in Hair Greying
The pace of this depigmentation process varies widely among individuals and depends primarily on genetic factors. People whose parents or grandparents experienced early greying face a higher likelihood of inheriting the same trait.
Sheila Bellotti, a trichologist and biomedical expert, explained that white hair occurs due to an anatomical phenomenon known as apoptosis, which is the programmed death of melanin-producing cells. Trichology is the branch of dermatology concerned with the health of the hair and scalp. Bellotti noted that melanocyte death is genetically determined, making heredity a crucial triggering factor. She added that in some families, individuals under the age of 18 develop white hair despite possessing a healthy, thick, and silky head of hair.
Impact of Stress and Health Conditions
Stress is also recognized as an accelerating factor in hair greying. Although stress is not the primary cause of grey hair, experts note that intense and prolonged stress can speed up depigmentation in individuals who are genetically predisposed.
Elevated levels of stress hormones can impair melanocyte stem cells, limiting their ability to regenerate. Regina Carralero, a specialist in hair health and trichology, explained that experimental studies show stress situations can intensely activate the sympathetic nervous system. This involuntary nervous system response affects the stem cells responsible for follicle pigmentation. Carralero highlighted that while this mechanism was demonstrated clearly in animal models, researchers must exercise caution before directly extrapolating the findings to human biology.
Nutritional deficiencies and underlying medical conditions can also cause hair to lose pigment prematurely. Deficiencies in vitamin B12 and iron, alongside thyroid disorders and certain autoimmune diseases affecting pigment production, are known contributing factors. Carralero noted that while no single food can prevent grey hair, deficiencies in vitamin B12, iron, and copper are associated with early greying in specific patients. Additionally, smoking accelerates the onset of white hair by increasing oxidative stress, a chemical process that damages cellular structures throughout the body.
Prevention and Treatment Evidence
There is currently no medical treatment capable of permanently preventing or reversing natural hair depigmentation. However, specialists emphasize that healthy lifestyle habits can preserve hair follicle function for a longer period.
Maintaining a balanced diet rich in essential vitamins and minerals, avoiding smoking, managing chronic health conditions, engaging in regular physical activity, and reducing stress all support overall cellular health and hair longevity. When a nutritional deficiency is medically confirmed, targeted correction can prevent it from contributing to early greying.
Conversely, products, dietary supplements, or cosmetic treatments marketed with claims to restore natural hair color lack scientific evidence. Bellotti explained that no scientifically proven method exists to stop greying or recover natural pigment, because genetic influence cannot be overridden. She emphasized that cellular aging and oxidative stress remain decisive factors that naturally limit melanocyte activity in the hair bulb.
