Phenylalanine is an amino acid, a “building block” of protein. L-Phenylalanine is an essential amino acid and is the only form of phenylalanine found in proteins.
Major dietary sources of L-Phenylalanine include meat, fish, eggs, cheese, and milk. L-Phenylalanine can be readily converted into the amino acid tyrosine.
Because tyrosine is necessary for the synthesis of proteins and the production of the neurotransmitters dopamine and norepinephrine, phenylalanine is an extremely important nutrient that must be obtained through the diet or supplementation.