NOW Foods L-Tyrosine 500 mg provides this conditionally essential amino acid that serves as the direct precursor to catecholamine neurotransmitters — dopamine, norepinephrine, and epinephrine — as well as thyroid hormones (T3 and T4). When the body is under physical or psychological stress, dopamine and norepinephrine are rapidly depleted, and supplemental tyrosine has been shown in military and cognitive research to maintain mental performance, focus, and stress resilience when these systems are taxed. Tyrosine supplementation is particularly effective taken before demanding cognitive tasks, high-stress situations, or intense training. As a thyroid precursor, it may also support energy levels and metabolism. NOW Foods delivers 500 mg of pharmaceutical-grade L-tyrosine per capsule, manufactured in their GMP-certified facility with identity and potency verification.