Hair loss

Keratinocytes in the skin metabolize vitamin D. These are skin cells responsible for the breakdown of keratin, a protein found in hair, nails, and skin. When the body lacks vitamin D, keratinocytes in hair follicles struggle to regulate hair growth and shedding. Low vitamin D levels have been linked to telogen effluvium, or excess hair shedding, alopecia areata, an autoimmune disorder in which hair falls out in clumps, and female pattern hair loss, according to a 2017 review published in the International Journal of Molecular Sciences.

According to a 2019 study published in the Indian Dermatology Online Journal, vitamin D deficiency can worsen hair loss over time. In addition, a 2016 study published in the International Journal of Trichology discovered that women with hair loss were more deficient in vitamin D than men. In one study of people with this condition, lower vitamin D levels were linked to more severe hair loss. Another study in 48 people with this condition found that applying a synthetic form of vitamin D topically for 12 weeks increased hair regrowth significantly. According to another study, vitamin D levels may have an inverse relationship with non-scarring hair loss. This means that higher vitamin D levels resulted in less hair loss in the study and vice versa.