L-Phenylalanine is an essential amino acid, one which is not synthesized by the body and must be obtained through diet or supplementation. L-Phenylalanine plays a key role in the biosynthesis of tyrosine, an amino acid required for the biosynthesis of the neurotransmitters dopamine and norepinephrine. This formulation provides Free Form L-Phenylalanine to promote optimal absorption and assimilation.*