Vitamin D and Hair Growth

The Biological Role of Vitamin D in Hair Follicles

The vitamin D receptor (VDR) plays a critical role in hair follicle cycling, and is essential for normal hair growth, with greatest activity during the anagen (growth) phase, as stated by the American Journal of Clinical Dermatology 1
Mutations in the VDR gene cause vitamin D-dependent rickets type II, which characteristically presents with sparse body hair and often total scalp alopecia, according to the American Journal of Clinical Dermatology 1

Multiple case-control studies consistently demonstrate lower vitamin D levels in patients with alopecia areata compared to healthy controls, with an odds ratio of 2.3 for vitamin D insufficiency, as reported by the American Journal of Clinical Dermatology 2, 3
An Egyptian study found that 83.3% of alopecia areata patients had vitamin D deficiency, versus 23.3% of controls, with vitamin D levels inversely correlating with disease severity, according to the American Journal of Clinical Dermatology 2, 3
A Turkish study found that 91% of alopecia areata patients were vitamin D deficient, versus 33% of controls, with a significant inverse correlation between vitamin D levels and severity, as stated by the American Journal of Clinical Dermatology 2, 3

Topical calcipotriol (0.005%) shows promise for treating patchy alopecia areata, with 59.1% of patients achieving hair regrowth, and patients with lowest baseline vitamin D levels having greatest improvement, as reported by the American Journal of Clinical Dermatology 3, 4, 5
A Turkish study found that 75% of patients achieved ≥50% hair regrowth after 12 weeks of topical calcipotriol treatment, according to the American Journal of Clinical Dermatology 3, 5

The American Journal of Clinical Dermatology recommends checking serum 25(OH)D levels in patients with alopecia areata, particularly moderate to severe disease, and supplementing to achieve normal levels if deficient 2, 3, 7
The American Journal of Clinical Dermatology suggests considering topical 0.005% calcipotriol twice daily for patchy alopecia areata in patients with documented vitamin D deficiency, but warns about potential side effects, including folliculitis 3, 4, 5, 6