L-tryptophan is an essential amino acid found, for example, in dairy products, nuts, seeds and pulses. The body uses it as a component of proteins and as a starting material for several metabolic pathways.
The pathway from tryptophan via serotonin to melatonin is particularly well known. Another important pathway is kynurenine metabolism, through which other compounds produced by the body can be formed. The conversions are controlled by various enzymes and micronutrients.
Amino acids differ in whether the human body can produce them itself. As components of proteins, many occur in protein-rich foods; some are also needed for other compounds produced by the body. The combination of different amino acids also influences the amino acid pattern of a food.
With amino acid preparations, it is worth looking at the actual form of the raw material. A free amino acid and its hydrochloride salt do not have the same chemical weight; the amounts may therefore differ. Different tablet or powder products, too, can only be compared meaningfully on the basis of the nutrient table.
In the Fairvital product L-Tryptophan 500mg, the formula shows the form and amount of the ingredients used. According to the list of ingredients, these include L-tryptophan. The composition table states 500 mg of L-tryptophan per capsule. The pack contains 90 capsules.