L-m-Tyrosine, also known as meta-tyrosine, is a non-proteinogenic amino acid analog of L-tyrosine used primarily in biochemical and pharmacological research. It acts as a competitive inhibitor of tyrosine hydroxylase, the rate-limiting enzyme in the biosynthesis of catecholamine neurotransmitters such as dopamine, norepinephrine, and epinephrine. By reducing the conversion of L-tyrosine to L-DOPA, L-m-Tyrosine depletes catecholamine levels, making it a valuable tool for studying the roles of these neurotransmitters in physiological and pathological conditions. Applications include research on hypertension, schizophrenia, drug-induced movement disorders, and the effects of catecholamine depletion in animal models. It is not used in dietary supplements for enhancing alertness or cognitive function, as its effects are inhibitory rather than stimulatory. In biotechnology, it may be employed in studies involving enzyme inhibition and neurotransmitter pathways, but it is not a standard nutritional additive in food or pharmaceutical formulations for mood regulation.