L-Tyrosine is an amino acid.
“Tyrosine is a nonessential amino acid the body makes from another amino acid called phenylalanine. It is an essential component for the production of several important brain chemicals called neurotransmitters, including epinephrine, norepinephrine, and dopamine. Neurotransmitters help nerve cells communicate and influence mood. Tyrosine also helps produce melanin, the pigment responsible for hair and skin color. It helps in the function of organs responsible for making and regulating hormones, including the adrenal, thyroid, and pituitary glands. It is involved in the structure of almost every protein in the body.” – UM Medical Center
I’m mostly interested in it because it is a precursor to dopamine. Dopamine is generally considered to not only be a feel good neurotransmitter (dopamine is released when someone gets high, eats sugar, gets a facebook notification, drinks diet coke, takes cocaine, etc.) but it’s also considered to be the motivation neurotransmitter.
Tyrosine also plays a role in the formation of melanin in the skin during tanning and a year ago I had trouble tanning.