5-HTP
Research Reliability -
A serotonin precursor that supports mood, sleep quality, appetite regulation, and relief from anxiety and stress.
Appetite
Mood
Sleep
5-HTP
Description
5-Hydroxytryptophan (5-HTP) is produced in the body from tryptophan and serves as the immediate precursor to serotonin, which is further converted to melatonin in the pineal gland. Unlike tryptophan, 5-HTP crosses the blood-brain barrier efficiently and has demonstrated benefits in multiple controlled trials for depression, anxiety, insomnia, fibromyalgia, and appetite control. It increases serotonin availability without requiring dietary tryptophan and can be a useful adjunct to transitional support from antidepressant therapy under physician guidance. Best taken in the evening due to its melatonin-supporting effects.
Effects
First dose
drowsy and calmer within 30–45 minutes
Same night
faster sleep onset and calmer appetite
Weeks 1–2
steadier mood as serotonin support builds
How It Feels
Most people feel drowsy and mellow within 30 to 45 minutes, which is why it is an evening supplement. Vivid dreams are common and some report morning grogginess if the dose is too high. Never combine it with SSRIs or other serotonergic drugs.
Evidence
Evidence Strength
Preliminary (limited / small human data)
Caveats
This Cochrane review noted the evidence base was too limited in quality to draw firm conclusions. Should not be combined with SSRIs or other serotonergic medications due to serotonin syndrome risk.
Usage
Commonly Referenced Starting Amount
50 mg/day
Commonly Referenced Amount
50–300 mg/day covers most mood and sleep research, though the supporting trials are small
Referenced Upper Limit
No upper limit has been established. This one needs real caution: combining 5-HTP with SSRIs, SNRIs, MAOIs, or other serotonergic medications can cause serotonin syndrome, a genuine medical emergency — don't stack this with antidepressants
Onset
30–45 min (acute); 2 weeks (sustained)
Biomarkers to Track
Subjective
(Daily)
Sleep onset latency (mins to fall asleep)
Morning mood score (1–10)
Hunger / craving intensity at bedtime
Objective
(Quarterly)
Whole blood serotonin level
Urinary 5-HIAA (serotonin metabolite)
HRV baseline (sleep quality proxy)
Effective but carries a real interaction: combined with serotonergic drugs it can cause serotonin syndrome.
Anyone on SSRIs, SNRIs, MAOIs, triptans, or tramadol, and pregnant women.
Combining it with antidepressants, taking it in the morning, and dosing too high (grogginess, vivid dreams).
Shaw K et al. (2002). Cochrane Database of Systematic Reviews. Meta-analysis (5-HTP for depression). PMID: 11869656.