Tyrosine is one of the lesser known amino acids, although it was identified way back in the nineteenth century, and indeed is described as one of those which are non-essential. Neither of these facts implies, however, that it is in any way unimportant. Tyrosine is one of the twenty or so separate amino acids found in the mammalian body; some of which are known as non-essential because they can be manufactured by the body, and need not therefore be consumed in the daily diet.

Ten amino acids, however, cannot be synthesised by the body, and must be obtained from food. Unsurprisingly perhaps, it is animal protein foods such as meat, fish and dairy produce which are the richest source, and they are accordingly known as first class proteins because they contain all of the essential amino acids.

The significance of both essential and non-essential amino acids, however, is that they form the proteins which make up the bulk of the dry tissue of the human body; most obviously the muscles. But the importance of protein goes way beyond this. The different proteins in the body also form the many enzymes which control its essential biochemical processes, including the secretion of vital hormones.

Tyrosine is formed in the body from the essential amino acid, phenylalanine, and in addition to its general role in the formation of proteins, appears to have a number of more specific functions.

Tyrosine appears to be directly involved in maintaining good supplies of the neurotransmitter hormones, adrenalin and noradrenalin, which are amongst the body's principal means of combatting stress, and its function within the brain have also led many nutritional practitioners to regard the amino acid as a powerful natural anti-depressant.

Some therapists report excellent results from the use of doses of up to 1,000 mg a day of tyrosine in treating even sufferers from the profound, clinical, depression characterised by apathy, inactivity, social withdrawal and even despair. An alleviation of even such extreme symptoms has been observed within as little as a week when patients have been treated with between 600 mg and 2,000 mg a day. The form of tyrosine known as acetyl L-tyrosine, however, appears to work more directly on the brain and doses of a few hundred mg per day of this compound may be sufficient.

In addition to cases of incapacitating clinical depression, tyrosine has also been found useful as a short term psychological tonic for times when an individual nay be suffering from particular stress, leading to reduced energy levels, confused thought or lowered mood. To this extent, tyrosine is also regarded by some as similar to an adaptogen, for example ginseng, in its general tonic effect.

In its effects on brain chemistry, tyrosine has also proved useful in alleviating conditions as diverse as Attention Deficit Disorder (ATD) and the symptoms arising from withdrawal from cocaine addiction. Tyrosine is also known to simulate the production of growth hormone and to stimulate the thyroid gland. Supplementation may therefore be useful in some cases of an underactive thyroid and the problems that this may cause.

In view of all the above, although it is not strictly necessary to obtain tyrosine from the daily diet, it does not follow that you should not seek to obtain as rich a supply as possible. If you're enjoying normal health, particularly mental and emotional health, you probably don't need to take supplements. But in view of the many benefits of tyrosine it is well worth ensuring that you take in a good dietary supply. This can only help with the stability of your moods, mental energy and focus.

The best foods for this purpose, of course, are the protein foods, whether vegetable or animal; in particular soy products, nuts, seeds, dairy produce, avocados, poultry and fish.

But if supplements are required at times of particular stress or increased energy requirement; tyrosine, like other single amino acids, is best taken on an empty stomach to ensure maximum absorption. As with other single amino supplements, however, these should not be taken in this way in the long term as this may risk the creation of nutritional imbalances. Like all other nutrients in the body, tyrosine can only do its work properly if the body is fully nourished in all other respects. When supplementing with tyrosine, however, it appears particularly important to ensure that generous supplies of vitamins B6 and C are present.

Since these vitamins also function holistically, this is as always best achieved by taking comprehensive multi-vitamin and multi-mineral supplements.

There appear to be no known problems of tyrosine toxicity at the dosages discussed in this article, but supplements at higher dose require medical supervision because there are contraindications for those suffering from high blood pressure or taking medication for migraine, Parkinson's disease, or being treated for certain cancers.