Vitamin D for hair growth and thickness refers to how this fat-soluble vitamin supports hair follicle cycling and prevents excessive shedding. Low vitamin D levels correlate with alopecia, but supplementation requires careful dosing.
Vitamin D influences hair growth through its role in keratinocyte proliferation and hair follicle stem cell regulation. The vitamin activates receptors in hair follicles, promoting anagen (growth) phase extension. A 2018 study in Dermatology Practical & Conceptual found 66% of alopecia patients had deficient vitamin D levels.
| Type | Source | Hair Impact |
|---|---|---|
| Vitamin D3 (Cholecalciferol) | Sunlight, fatty fish, fortified foods | Most bioavailable form; directly supports follicle cycling |
| Vitamin D2 (Ergocalciferol) | Plant sources, mushrooms | Less effective than D3 for hair health |
The Mayo Clinic recommends 20-50 ng/mL serum levels for general health. For hair-specific benefits, research suggests 30-40 ng/mL may be ideal. Severe deficiency (<10 ng/mL) correlates with diffuse hair thinning patterns. Over-supplementation (>100 ng/mL) causes toxicity symptoms including hair loss.