Does D matter? The role of vitamin D in hair disorders and hair follicle cycling.

BACKGROUND: The role of vitamin D in the proliferation and differentiation of keratinocytes is well known within the field of dermatology.

OBJECTIVE: We sought to evaluate the role that vitamin D and the vitamin D receptor play in the hair cycle and assess how this can be clinically applied to the treatment of hair disorders.

METHODS: A MEDLINE search (1955-July 2009) was preformed to find relevant articles pertaining to vitamin D, the vitamin D receptor, and hair loss.

RESULTS: The vitamin D receptor, independent of vitamin D, plays an important role in hair cycling, specifically anagen initiation. The role of vitamin D in hair follicle cycling is not as well understood.

LIMITATIONS: The review is broad and there are limited human studies available to date.

CONCLUSION: Additional studies to evaluate the role of vitamin D in the hair cycle should be done. Treatments that up regulate the vitamin D receptor may be successful in treating hair disorders and are a potential area of further study.