Medically reviewed by Aviv Joshua, MS, RDN Phenylalanine is an essential amino acid (building block of protein) that the body doesn't produce, meaning it must be obtained through food. It is found in ...

Melanin is a natural pigment in your body that protects you from UV damage from the sun. People with darker skin tend to have more melanin and are therefore at a lower risk of sun damage.

Melanin is a protein that pigments, or colors, your eyes as well as your skin. The iris is divided into two layers. Almost everyone has melanin in the back layer. The amount of melanin in the ...