Biotin
Over the years, the benefits of biotin on hair growth may have been exaggerated a bit — it’s not a cure-all for all hair issues. But it remains important because biotin (known as B7) helps produce keratin, which is a protein needed for strong hair, skin, and nails. The recommended daily intake of biotin is 30 micrograms (mcg) for adults and 35 mcg for pregnant people. It’s rare to have a biotin deficiency, and if you can obtain this nutrient from foods like egg yolks, salmon, legumes, and walnuts, all the better.
Vitamin A
Vitamin a promotes healthy blood circulation, which is important for hair follicle stimulation, sebum production to regulate the oils on your scalp and keep hair shiny and health, cell grown, and it protects hair and skin from free radicals. The recommended dietary allowance (RDA) of vitamin A is 700 micrograms for women and 900 micrograms for men. Be careful when taking Vitamin A supplements because you can take too much and it can cause toxicity. Getting this nutrient from foods like eggs, sweet potatoes, spinach, and fortified milk is a good idea.
Vitamin C
Vitamin C is responsible for helping your body produce collagen, which repairs and renews tissue and can help with new hair growth. It also aids your body in absorbing important nutrients needed for hair health, like iron. Consider it a best friend to the body — and try to get as much of it as you can from foods like citrus fruits, peppers, and tomatoes. The DV for vitamin C is 90 mg for adults and children age 4 years and older
Iron
Iron is so important for your body and hair because it helps your body produce hemoglobin, which is a protein found in red blood cells that carries oxygen to your body’s cells, helping them repair and grow. Among those cells are cells responsible for hair growth. This is one mineral that some women are deficient in, and a supplement can help (check with your doctor first). The Recommended Dietary Allowance (RDA) for all age groups of men and postmenopausal women is 8 mg/day; the RDA for premenopausal women is 18 mg/day. The median dietary intake of iron is approximately 16 to 18 mg/day for men and 12 mg/day for women.
Vitamin D
Vitamin D actually works directly with hair follicles to help them grow properly and it gives your body a signal to start the anagen (growth) phase for hair. The DV for vitamin D is 20 mcg (800 IU) for adults and it can be found in foods like fatty fish and milk — as well as sunlight (wear sunscreen when out though).
Vitamin E
Vitamin E has antioxidant effects that reduce the amount of oxidative stress getting in the way of healthy hair growth and help strengthen your scalp and strands. Vitamin E can also improve blood supply to the scalp, which helps boost hair follicles into action. You’ll find this nutrient in avocado, broccoli, mango, and nuts, including almonds and the DV for women is 15 mg.
Zinc
Zinc supports hair growth by helping to produce DNA and RNA, which are important for cell division in hair follicles. Zinc also helps produce and regulate collagen, not to mention it’s a key player in inhibiting 5α-reductase type 1 and 2 activity, according to studies, which helps hair growth. The daily recommended allowance is between 8 and 11 mg and zinc can be found in foods like beans, oats, pumpkin seeds, oysters, and lean beef.