Iodine
Iodine is vital to your hair growth. Sheep farmers long ago found that vegetation-lacking iodine due to iodine-depleted soil would adversely affect the growth of wool in their sheep. Likewise, to avoid hair loss, you need iodine. Iodine is synthetically added to table salt, however in this form it is not assimilated well into your body and can therefore cause iodine overload.