Tyrosine (L-form) is a non-essential amino acid, which is primarily required for the protein synthesis. This amino acid is the precursor of dopamine, norepinephrine, and epinephrine; therefore the lower concentration of tyrosine could be a peripheral marker of the hyperdopaminergic condition hypothesized to explain psychosis. Tyrosine supplements can improve cognition, increase energy, reduce anxiety, reduce depression, reduce levels of pain.

N-Acetyltyrosine is an acetylated derivative of the amino acid L-tyrosine. Ordinary L-tyrosine is less stable and also less soluble in water, which may result in reduced bioavailability. Acetylation enhances the solubility and stability of certain amino acids. N-Acetyltyrosine is commonly used in place of tyrosine in parenteral nutrition. It converts to tyrosine and then can be used in neurotransmitter treatment as a precursor of cathecholamine. N-Acetyltyrosine supports brain function by supporting the synthesis of the catecholamines norepinephrine and dopamine (neurotransmitters). N-Acetyltyrosine supplements are used to improve memory and cognitive performance in humans while they are experiencing psychological stress.