Welcome again to EmpowHER. Thank you for addressing the issue of premature greying and possible causes.
Premature greying is largely linked to genetics. Hair follicles contain pigment cells that produce melanin. When your body stops generating melanin, hair presents itself as gray, white, or silver.
Race and ethnicity play a role in the graying timeline, too: Whites typically start to notice gray strands around age 35, while African-Americans tend to be 40 when it begins. About 50 percent of people have half a head of gray by the time they're 50.