A vital, an important mineral, may affect hair health and hair growth through its effects on thyroid function. Iodine can also be sometimes prescribed as a topical treatment for certain conditions that cause hair loss on the scalp. To help prevent thyroid problems that will cause hair problems, it’s important to get sufficient dietary iodine. Per the recommended daily allowances for iodine, adults need 100 mcg to 200 mcg of dietary iodine daily. You should not take iodine supplements without first consulting your doctor, however.