Human Hair Graying Revisited: Principles, Misconceptions, and Key Research Frontiers

The review delves into the complex mechanisms of human hair graying, highlighting its psychosocial significance and potential as a model for studying pigmentation and aging. Graying is attributed to oxidative and DNA damage, excessive mTORC1 activity, melanocyte senescence, and inadequate pigmentation-promoting factors, with genetic and environmental influences playing roles. It becomes irreversible when bulge melanocyte stem cells are depleted. However, temporary reversibility through drugs and hormones is possible, suggesting pathways for future antigraying strategies. The review advises caution in applying mouse model findings to humans and underscores the need for further research to understand and potentially reverse hair graying.