Need Assistance?

  • US & Canada:
  • UK: +
* Please kindly note that our products are not to be used for therapeutic purposes and cannot be sold to patients.

5-Hydroxytryptophan (5-HTP), also known as oxitriptan (INN), is a naturally occurring amino acid and chemical precursor for the treatment of depression. 5-Hydroxytryptophan can be used as a dietary supplement (health product).

DL-Amino Acids
Catalog number
CAS number
Molecular Formula
Molecular Weight
Size Price Stock Quantity
25 g $458 In stock
2-amino-3-(5-hydroxy-1H-indol-3-yl)propanoic acid
5-Hydroxy-DL-tryptophan; DL-5-Hydroxytryptophan; H-DL-Trp(5-OH)-OH
White powder
1.484 g/cm3
Melting Point
>215°C (dec.)
InChI Key
Canonical SMILES
1.Molecular basis of 5-hydroxytryptophan synthesis in Saccharomyces cerevisiae.
Zhang J1, Wu C2, Sheng J2, Feng X2. Mol Biosyst. 2016 Apr 26;12(5):1432-5. doi: 10.1039/c5mb00888c.
We report for the first time that 5-hydroxytryptophan can be synthesized in Saccharomyces cerevisiae by heterologously expressing prokaryotic phenylalanine 4-hydroxylase or eukaryotic tryptophan 3/5-hydroxylase, together with enhanced synthesis of MH4 or BH4 cofactors. The innate DFR1 gene in the folate synthesis pathway was found to play pivotal roles in 5-hydroxytryptophan synthesis.
2.SSRI Augmentation by 5-Hydroxytryptophan Slow Release: Mouse Pharmacodynamic Proof of Concept.
Jacobsen JP1, Rudder ML1, Roberts W1, Royer EL1, Robinson TJ1, Oh A1, Spasojevic I2, Sachs BD1, Caron MG1,2,3. Neuropsychopharmacology. 2016 Mar 2. doi: 10.1038/npp.2016.35. [Epub ahead of print]
Drugs, notably SSRIs, that elevate brain extracellular 5-HT (5-HTExt) are antidepressants. Unfortunately, most patients fail to remit. Multipronged clinical evidence suggests that elevating 5-HTExt beyond the SSRI effect enhances antidepressant efficacy, but previous such drug strategies had prohibitive limitations. In humans, adjunct treatment with the 5-HT precursor 5-hydroxytryptophan (5-HTP) elevates 5-HTExt beyond the SSRI effect. Small pilot trials suggest that adjunct 5-HTP can confer antidepressant response in treatment-resistant depression (TRD). However, sustained, stable 5-HTExt elevation is required for antidepressant effect; therefore, the rapid absorption and elimination of standard 5-HTP immediate release (IR) likely curtail 5-HTP IR's antidepressant potential. Slow-release (SR) drug delivery can crucially improve efficacy and safety of rapidly absorbed and eliminated compounds. Here we tested in mice the hypothesis that SR delivery will substantially improve 5-HTP's drug properties, by minimizing adverse effects and securing sustained 5-HTExt elevation beyond the SSRI effect.
3.Comparison of 5-hydroxytryptophan signaling pathway characteristics in diarrhea-predominant irritable bowel syndrome and ulcerative colitis.
Yu FY1, Huang SG1, Zhang HY1, Ye H1, Chi HG1, Zou Y1, Lv RX1, Zheng XB1. World J Gastroenterol. 2016 Mar 28;22(12):3451-9. doi: 10.3748/wjg.v22.i12.3451.
AIM: To study differences in the visceral sensitivity of the colonic mucosa between patients with diarrhea-predominant irritable bowel syndrome (IBS-D) and those with ulcerative colitis (UC) in remission and to relate these differences with changes in the 5-hydroxytryptophan (5-HT) signaling pathway.

Online Inquiry

Verification code
Inquiry Basket