While stress, lifestyle and nutrition can influence when hair turns gray, genetics remain the primary determining factor, according to a Turkish medical genetics expert.
Professor Zeynep Ocak, head of the Genetic Diseases Diagnosis and Evaluation Center at Biruni University Medical Faculty Hospital, said hair graying is not always directly tied to aging. Some individuals begin to see gray strands in their 20s, while others may retain fully pigmented hair into their 50s.
She explained that hair color is determined by melanin, a pigment produced by melanocyte cells located in hair follicles. The more active these cells are, the darker the hair appears.
Over time, melanocyte activity decreases or stops entirely, leading hair to first turn gray and eventually white. Ocak said the timing of this process varies widely among individuals, but genetic factors are the primary driver.
“Individuals with a family history of early graying are at significantly higher risk of experiencing the same condition,” Ocak said in a statement. She added that genes such as IRF4, MC1R and MITF directly affect melanin production and the life span of pigment-producing cells.
Ocak also addressed the common belief that stress can turn hair gray overnight, saying there is no full scientific basis for the claim, though stress may have an indirect effect.
“Long-term stress can damage stem cells in hair follicles,” she said. “In individuals with genetic predisposition, this may contribute to earlier onset of graying.”
She noted that graying before age 30 is considered “premature graying” and may sometimes signal vitamin or mineral deficiencies, particularly in vitamin-B12, iron and copper. In rarer cases, it can be associated with genetic disorders.
Hair graying is also influenced by ethnicity, Ocak said. Individuals of European descent tend to experience earlier and more complete graying, while populations of Sub-Saharan African descent generally experience later and less extensive graying.
Ocak emphasized that there is currently no treatment that can fully stop the biological process of hair graying, although research continues.
“Hair graying is not a disease, but a natural biological process,” she said. “Hair dyes offer a temporary solution, but it is not possible to completely stop the process. Hair graying is often a script written by genes. Stress, lifestyle and nutrition may accelerate it, but genetics play the leading role.”
