Tyrosine should be taken in through the diet as the body is unable to produce it. Tyrosine is an organic chemical compound. It performs important biological tasks as an intracellular transmitter (it can be phosphorylated by protein kinases), and is also a precursor to important hormones and biologically active substances (thyroxine, triiodothyronine, adrenaline, noradrenaline and dopamine). It is an endogenous amino acid, which means that the human body and most animals are able to synthesize it provided that there is sufficient supply of phenylalanine, from which tyrosine differs by the presence of one hydroxyl group. Tyrosine is very important for the proper functioning of the thyroid and pituitary gland. Lack of this amino acid causes hypothyroidism, which can manifest itself in the form of fatigue and exhaustion. Reducing the amount of tyrosine in the body causes a deficiency of norepinephrine and dopamine, which can cause depression.
