The vitamins with the best claims for promoting hair health and growth are vitamin B and vitamin D, Healthline states. Other helpful vitamins include the B-complex group and vitamins A, D, E, K and C.
B-complex vitamins are important for hair and skin health, Healthline reports. These vitamins play a role in metabolism and the functioning of the central nervous system. They are available from foods such as carrots, legumes, beef liver, poultry, eggs, nuts, avocados and soybeans. Vitamin B-12, or cobalamin, is available from meat and dairy products. One of the more popular B vitamins, biotin, has been recommended by experts for its hair benefits; however, evidence for its efficacy is all but lacking. Excessive amounts of biotin may disrupt insulin release and cause skin-related issues.
Vitamin D has been linked to hair growth by multiple studies, Healthline notes. A 2012 study reported that vitamin D may be able to cause new follicles to develop. According to research at Harvard, vitamin D may also play a role in stimulating follicles that have fallen dormant and no longer create new hair. Vitamin D is available from foods including grains, mushrooms, swordfish and salmon. Other sources include low-fat fortified milk, fortified orange juice, supplements and exposure to sunlight. (The body produces vitamin D when exposed to sunlight.)