Eating a healthy diet is the only way to truly nourish hair. Substances applied from the outside can only improve appearance and texture.
Hair needs the same spectrum of nutrients as the rest of the body, and some are especially beneficial. For example, hair is largely protein. Meat and dairy foods pack the most protein punch, with soy foods running a close second. Biotin, a B vitamin, promotes softness and strength. It's found in brown rice, leafy greens and eggs. The omega-3 fatty acids in fish and nuts are especially good for the scalp. Getting enough fluid in both food and drink is also essential to handsome hair.
And exercise? It increases the blood flow, delivering all those nutrients to your scalp -- which, you'll remember, is where healthy hair starts.