L-Tyrosine is a conditionally essential amino acid, which occurs naturally in foods, mainly as part of proteins. It is one of the 22 amino acids that are used by cells to synthesize proteins. Dietary L-Tyrosine is provided by mixed dietary protein intakes from different sources and it can also be consumed in the form of supplements. It’s popular among athletes to take pure L-Tyrosine before workouts, especially with Caffeine.