Tyrosine is not biochemically defined as an essential amino acid in adulthood (it can become so in conditions of phenylalanine deficiency), but it is still key for the human organism; besides being derived from food, tyrosine can indeed be synthesised from phenylalanine by simple addition of a hydroxyl group (OH) to its aromatic ring. Tyrosine is the starting amino acid for the synthesis of fundamental neurotransmitters, such as dopamine, adrenaline and noradrenaline. These last two substances are very important for the process of adaptation of our body to intense and sudden psychophysical stresses, supporting our mood and improving depressive states and anxiety. Thus, by increasing the levels of epinephrine, norepinephrine, and dopamine neurotransmitters, tyrosine manages to influence a wide range of processes and functions within the body, particularly those involved in the functions related to vigilance, attention and mood. For this reason, we can define tyrosine as an amino acid with adaptogenic effects, which is used (among the various activities in which it is involved) particularly to improve the body s response to various kinds of stresses which the body undergoes on a daily basis. L-tyrosine can help athletes avoid problems arising from excessive training, because its properties allow counterbalancing physical and mental fatigue and improve the sense of well-being and concentration. Moreover, L-tyrosine is useful for protecting the skin integrity, as melanin is a derivative of L-tyrosine. If the body is low on or lacks melanin, the skin s defenses may be compromised. Melanin, which comes from L-tyrosine and reacts chemically in sunlight, helps create a protective screen for the deeper layers of skin tissue. Here, tyrosine is also required for the synthesis of melanin, which is the skin pigment responsible for tanning and skin colour, further to that of eyes and hair. It also participates in the synthesis of various hormones, such as the thyroid ones, of blood elements such as red and white blood cells, as well as intervening in protein synthesis and thus re-entering most of the body s protein structures. Where there is a need to supplement L-Tyrosine, it is clear that it is considered a safe supplement. Possible side effects (in the case of high doses are related to gastrointestinal disorders). Tyrosine should not be taken by individuals with arterial hypertension and by those taking non-selective monoamine oxidase inhibitors or related to L-Dopa therapy in Parkinson s. Supplementation is also discouraged for those suffering from headaches and those suffering from phenylketonuria and malignant pigmented melanoma.
