Find Search

Other Information

Quest Vitamins LTD,
8 Venture Way,
Aston Science Park,
B7 4AP.

Tel: 0121 359 0056
Fax: 0121 359 0313
Registered in England No. 2530437



L-tyrosine is a non-essential amino acid that can be made from L-phenylalanine in the body.


As well as being incorporated into body proteins, L-tyrosine is the raw material from which a group of neurotransmitters (brain chemicals) called catecholamines are formed.

One of the catecholamines formed from L-tyrosine is adrenalin. Adrenalin, together with other neurotransmitters, helps to focus the mind and improve concentration during Stress (1).

L-tyrosine is also the precursor for thyroid hormone and the Skin pigment melanin (2).


L-tyrosine taken as a supplement has produced excellent results in some types of Depression - specifically tired, apathetic depression as opposed to high Anxiety states. Put simply, L-tyrosine helps replace excitatory neurotransmitters depleted by stress (1,3,4).

Similarly, L-tyrosine supplements are to be recommended in cases of low motivation or poor concentration (1).


Up to 6g/day of L-tyrosine appears to be perfectly safe in human adults, but no more than 2000mg daily is usually necessary for good effect.


L-tyrosine should be avoided by those with high blood pressure or melanoma

MAO inhibitor anti-depressant drugs: It should also not be taken by those on MAO inhibitor anti-depressant drugs.

L-tyrosine should additionally not be taken by pregnant women or schizophrenics.


1. "The Healing Nutrients Within", E R Braverman & C C Pfeiffer, Keats, 1987.
2. Santana C, et al. Changes in tyrosine hydroxylase activity and melatonin synthesis in rat pineal glands throughout 72 hours of incubation. Neurosci Lett, 173;1-2:119-123 1994.
3. Kaneko M, Watanabe Km Kumashiro H. Plasma ratios of tryptophan and tyrosine to other large neutral Amino Acids in manic-depressive patients. Jpn J Psychiatry Neurol, 46;3:711-720 1992.
4.Fernstrom JD. Dietary Amino Acids and brain function. J Am Diet Assoc, 94;1:71-77 1994.