Tryptophan and 5-hydroxy-tryptophan, for instance, can be used to help the body replenish serotonin levels in the brain after the use of MDMA, and vitamin supplements are appropriate for users of stimulants such as amphetamine.
Tryptophan, an essential amino acid in the human diet (mRNA genetic code)
The key amino acids of the BSCI peptides required for activity have been identified, and the tripeptide AcNH-Trp-Val-Gln-OH was shown to itself be a BSCI in the low micromolar range.
Kynurenic acid, a product of the normal metabolism of amino acid L-tryptophan
An efficient conversion of tryptophan to indole-3-acetic acid and/or tryptophol can be achieved by some species of fungi in the genus Rhizoctonia.