Neurotransmitter Support Pharmaceutical Grade Healthy Glandular Function Supports Metnal Alertness Non-GMO A Dietary Supplement Amino Acids Family Owned Since 1968 GMP Quality Assured L-Tyrosine is a conditionally indispensable amino acid required for the production of the neurotransmitters dopamine, adrenaline, and noradrenaline, as well as for the skin pigment, melanin. Noradrenaline (norepinephrine) and adrenaline (epinephrine) are the main actors in the body's response to acute stress and, along with dopamine, help to support a positive mood and mental alertness. In addition, L-Tyrosine is especially critical for the normal function of the thyroid gland.