Vitamin D and the skin: Focus on a complex relationship: A review

The 2015 review highlights the multifaceted role of vitamin D in skin health, including its importance in immune function, hair follicle cycling, sebaceous gland function, and protection against UV damage. It suggests that vitamin D deficiency may contribute to skin diseases such as psoriasis, acne, rosacea, and various forms of alopecia, and that vitamin D receptors are crucial for hair cycle regulation. While vitamin D analogs are used in treating conditions like psoriasis and vitiligo, the review acknowledges that the evidence linking vitamin D to the prevention of skin cancer and the treatment of hair loss is not conclusive. It emphasizes the need for further research to fully understand the relationship between vitamin D and skin disorders and to develop clear supplementation guidelines. The review also notes that maintaining an optimal 25-hydroxyvitamin D level of 75 nmol/L or higher is suggested for overall health and skin function.