Tyrosine is a nonessential amino acid because the body can make it from phenylalanine. Tyrosine improves alertness, attention and focus as dietary supplement. Tyrosine is an essential component for the production of several important brain chemicals to help nerve cells communicate and may even regulate mood. It also helps produce melanin, the pigment responsible for hair and skin color. It helps in the function of organs responsible for making and regulating hormones. It is involved in the structure of almost every protein in the body.