5-hydroxy Tryptophol is a metabolite of tryptophan.

Tryptophan (encoded by the codon UGG) is an α-amino acid that is used in the biosynthesis of proteins. Tryptophan has an α-amino group, an α-carboxylic acid group, and a side chain indole, demonstrating it as a non-polar, aromatic amino acid. Tryptophan is critical in humans, but the body cannot synthesize it and therefore tryptophan must be obtained from the diet. Tryptophan is also found to be a precursor to the neurotransmitters serotonin and melatonin.

In vitro: In previous studies, 5-hydroxy tryptophol was identified as a metabolite of tryptophan that was formed by the alcohol dehydrogenase-catalyzed reduction of the serotonin intermediate, 5-hydroxyindoleacetaldehyde. Moreover, depending on the tissue NAD/NADH ratio, the acetaldehyde intermediate could also be oxidized by aldehyde dehydrogenase to form 5-hydroxyindoleacetic acid. Therefore, the ratio of 5-hydroxy tryptophol to 5-hydroxyindoleacetic acid could be used as a biomarker for recent alcohol consumption [1,2].

In vivo: Up to now, there is no animal in vivo data reported.

Clinical trial: So far, no clinical study has been conducted.

References:
[1] Yokoyama, M. T. and Carlson, J.R. Dissimilation of tryptophan and related indolic compounds by ruminal microorganisms in vitro. Appl.Microbiol. 27(3), 540-548 (1974).
[2] Beck, O. ,Stephanson, N.,Btthcer, M., et al. Biomarkers to disclose recent intake of alcohol: Potential of 5-hydroxytryptophol glucuronide testing using new direct UPLC-tandem MS and ELISA methods. Alcohol & Alcoholism 42(4), 321-325 (2007).