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.