5-HTP
A direct serotonin precursor sold for sleep and mood, on thin evidence, with a serious drug interaction.
C-
Evidence grade
C-
Worth it
$8-15/month
Typical cost
DoseNo dose is established by rigorous trials. Products are commonly sold at 50 to 300 mg a day, often taken at night for sleep or in divided doses for mood. The dose question matters less than the interaction question: anyone taking an SSRI, SNRI, MAOI, tramadol, or another serotonergic drug should treat 5-HTP as a clinician conversation, not a purchase, because the combination can contribute to serotonin syndrome.
BasisThe evidence is thin in both claimed directions: the depression trials are few, small, and decades old, and the sleep data are small and indirect.
5-HTP (5-hydroxytryptophan) is the direct precursor to serotonin: the body converts it to serotonin and then to melatonin. We grade 5-HTP C- on evidence and C- for worth-it at about $8-15 per month.
What it does
5-HTP (5-hydroxytryptophan) is the direct precursor to serotonin: the body converts it to serotonin and then to melatonin. It is produced commercially from the seeds of the African plant Griffonia simplicifolia and sold for mood and sleep. Because it raises serotonin directly, it also interacts with every drug that raises serotonin, and that interaction is the centre of this record.
What the research says
May support mood in depression
Evidence: weak. The depression literature is small, old, and low quality: a Cochrane-era review of the tryptophan and 5-HTP trials found too few rigorous studies to conclude benefit. What exists is mostly short trials from the 1980s and 1990s, run before modern trial standards.
May help sleep
Evidence: weak. Sleep evidence is small and indirect. 5-HTP feeds the serotonin-to-melatonin pathway, which is the plausibility case, and a handful of small studies report sleep changes. No adequately sized trial has tested it for insomnia as the primary question.
The evidence is thin in both claimed directions: the depression trials are few, small, and decades old, and the sleep data are small and indirect. The grade is also held down by the interaction profile, not only by the thin results: this compound’s main documented risk lands on the exact audience a sleep or mood product reaches, people already taking serotonergic medication. C- is an evidence grade with the safety discount stated openly.
Is it worth it?
Evidence (C-) sits below the leaderboard floor, which caps the worth-it grade at C+ however it is priced; the derived value at about $12 a month lands at C-. The interaction profile is the practical argument against casual use at any price. Derived from the October 2026 worth-it model.
Typical cost
$8-15/month
Common form, not a brand recommendation
Dosage context no established dose
No dose is established by rigorous trials. Products are commonly sold at 50 to 300 mg a day, often taken at night for sleep or in divided doses for mood. The dose question matters less than the interaction question: anyone taking an SSRI, SNRI, MAOI, tramadol, or another serotonergic drug should treat 5-HTP as a clinician conversation, not a purchase, because the combination can contribute to serotonin syndrome.
Worth-it leaderboard
5-HTP sits outside the worth-it top 20.
5-HTP sits outside the current top 20 on the gated leaderboard. The leaders below clear an evidence floor of B- before price counts at all, so cheap alone never earns a rank.
- 1AWorth itCreatine evidence A-~$5-10/mo
- 2AWorth itCaffeine evidence B+~$5-10/mo
- 3AWorth itVitamin D evidence B~$5-8/mo
See the full worth-it leaderboard →
When the evidence moves a grade, this ranking moves with it. Thursday is where you hear it first.
Safety notes
Serotonin syndrome is the material risk: combined with SSRIs, SNRIs, MAOIs, tramadol, triptans, or other serotonergic agents, 5-HTP can push serotonin too high. Symptoms include agitation, fever, tremor, and confusion, and the severe form is a medical emergency. Do not combine it with those drugs outside clinician supervision. Historical note: the 1989 eosinophilia-myalgia syndrome outbreak was traced to a contaminated supply of the related amino acid tryptophan; it stands as a manufacturing caution for this supplement family rather than a finding about modern 5-HTP itself. Nausea and stomach upset are the common side effects at higher doses.
Longevity Lab Report
5-HTP news. Graded when it happens.
The grade on this page stays free. The email carries the news on 5-HTP: expert moves, dose changes, and what is working, in plain English every Thursday.
Changelog
Last updated 2026-10-27
- 2026-10-26|Graded in the weekly deep dive of 2026-10-26 (C-), from the Oct 25 queue intake. The record is built around its safety centre: a direct serotonin precursor whose material interaction is serotonin syndrome alongside SSRIs, SNRIs, MAOIs, and tramadol. It jumped the grading queue on that asymmetry (Research ruling, 2026-10-25) after appearing in a viral sleep product formula, and any dose answer for this record carries the interaction caution in its lead.
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This grade for 5-HTP rests on the record above. When a new result changes that record, the grade changes with it, and the Thursday email is where the change lands first: the week's longevity and biohacking news, in plain English, linked back to the reasoning on this page.
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