500 mg Free-Form L-Phenylalanine is an essential amino acid that is necessary for the synthesis of proteins.* Because L-Phenylalanine can be readily converted into the amino acid tyrosine, which forms part of the structure of the neurotransmittters dopamine and norepinephrine, it is important for the maintenance of a healthy nervous system.* Natural color variation may occur in this product. Settling of powder may occur in the capsule, which is filled by weight without added fillers.