What is L-tyrosine?

L-Tyrosine is an amino acid found in the diet that is metabolized to produce catecholamines such as dopamine (DA) and norepinephrine (NE).^[1] L-tyrosine is also used in the production of thyroid hormones.^[2] L-Tyrosine is often taken as a supplement to help increase catecholamine levels depleted during stressful or challenging conditions.^[1] It is taken as a free-form amino acid supplement, commonly alone or as part of weight loss or preworkout supplements.