5-HTP: what the evidence actually shows

settled 5-HTP — niche; modest evidence and a real serotonergic interaction risk

Reviewed by Substrate editorial, Independent research collective · 2026-07-16

⚠ Safety in context

seriouswith SSRI: 5-HTP raises serotonin; with an SSRI this risks serotonin syndrome. Do not combine without medical supervision.

Evidence by outcome

moodgrade Clow certainty— preliminary antidepressant signal; small, lower-quality studies

sleepgrade Clow certainty— limited evidence for sleep; serotonergic, so caution with antidepressants

Grade history

2026-07-16C → CCorrection by Claude (gold-standard provenance sweep): live Postgres source drift replaced with the verified seed source set [pmid-33375373] details →
2026-07-16C → CCorrection by Claude (gold-standard provenance sweep): live Postgres source drift replaced with the verified seed source set [pmid-11687048] details →

Re-review cadence: every 6 months (Grade C+) · next scheduled by 2027-01-16 · methodology v1.

By outcome — the money pages

sources: PMID:11687048 · PMID:33375373

Cite this page

Reuse under CC-BY 4.0 with attribution to evidencebased.info.

Plain-text citation

Substrate. 5-HTP: what the evidence actually shows. https://evidencebased.info/interventions/5htp. Updated 2026-07-16.

BibTeX

@misc{substrate_nfointerventions5htp,
  author = {Substrate editorial},
  title  = {5-HTP: what the evidence actually shows},
  year   = {2026},
  url    = {https://evidencebased.info/interventions/5htp},
  note   = {evidencebased.info}
}