Serotonin a la carte: supplementation with the serotonin precursor 5-hydroxytryptophan
Turner EH, Loftis JM, Blackwell AD
Published in Pharmacology & Therapeutics
Methodology
Critical narrative review of 5-HTP pharmacology, clinical trial evidence and safety, including the eosinophilia-myalgia literature.
Key Findings
5-HTP readily crosses the blood-brain barrier and raises CNS serotonin, but clinical trials are small, old and methodologically weak. The review highlights the risk of cardiac valvulopathy from peripheral serotonin, interaction with serotonergic drugs, and unresolved contamination concerns.
Conclusions
5-HTP has plausible pharmacology but the human evidence remains inadequate, and safety concerns argue against unsupervised long-term use.
Limitations
Narrative review without systematic search or pooled effect estimates.
Supplements Studied
5-HTP raises CNS serotonin readily, but the clinical trial base is small and dated, and peripheral serotonin exposure raises valvulopathy and drug-interaction concerns.
Peripheral serotonin precursor loading raises brain serotonin synthesis, but clinical outcomes depend heavily on baseline status.
Related Health Concerns
Study Details
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Disclosures
Funding
Academic (Oregon Health & Science University); no commercial sponsorship reported.
This information is for educational purposes only. Always consult a healthcare professional before starting any supplement regimen.