Approximately five hundred amino acids occur in nature. Twenty of these are amino acids that serve as building blocks for proteins in the human body, these are referred to as 'fundamental amino acids'. These fundamental amino acids can be further subdivided into the categories 'essential', 'semi-essential' and 'non-essential'. L-tryptophan belongs to the so-called essential amino acids, which means that the body cannot produce it itself from other amino acids, and that one is completely dependent on food in order to meet one's daily needs.

Tryptophan occurs in food in quantities that are too small to be used as a source for the production of supplements. Tryptophan for use in a supplement is therefore usually produced by means of a specially developed fermentation process. Micro-organisms can synthesize tryptophan themselves, and this property is used in this process. The natural L-form of tryptophan is created. The synthetic D-form is not effective and can reduce the biological availability of the natural L-form. Supplementation with D-tryptophan is therefore not recommended.

Tryptophan is, among other things, the precursor of niacin (vitamin B3), 5-HTP (5-hydroxytryptophan), the neurotransmitter serotonin and the hormone melatonin. It can cross the blood-brain barrier, but is sensitive to competition with other amino acids. A tryptophan supplement should therefore preferably be taken on an empty stomach, separately from other amino acids.

Permitted health claims:
No.

L-tryptophan, anti-caking agent (rice fibre), vegetable capsule (pullulan, from fermented cassava starch).