amino acid · for low mood
5-HTP
One step away from serotonin, and it reaches the brain readily.
Say that in clinical terms
Direct precursor to serotonin, bypassing rate-limiting tryptophan hydroxylase step. Crosses BBB readily.
How strong is the research?
Evidence evidence
Low-quality evidence
2 papers read, 2 supporting.
Who was studied: Mostly people diagnosed with depression by a psychiatrist.
How much to take
daily
50–300 mg
Start low (50mg) and titrate up. Do NOT combine with SSRIs/MAOIs (serotonin syndrome risk).
Before you take it
- Serotonin syndrome risk: contraindicated with SSRIs, SNRIs, MAOIs, triptans, tramadol, linezolid, dextromethorphan, MDMA, St. John's Wort, SAMe, and L-tryptophan — pharmacodynamic interaction requiring avoidance, not timing separation
- Linezolid (antibiotic with MAOI activity): contraindicated — serotonin syndrome cases documented with 5-HTP co-administration
- Eosinophilia-Myalgia Syndrome (EMS) risk: Peak X family contaminants detected in all 8 commercially tested 5-HTP products analyzed by HPLC-MS (FDA advisory issued late 1990s); NIH urges cautious use; whether EMS is caused by 5-HTP itself or by contaminants is not established
- Lab interference: 5-HTP elevates urinary 5-HIAA, which may produce false-positive carcinoid tumor test results
- No NIH/IOM Tolerable Upper Intake Level (UL) has been established for 5-HTP
- Pregnancy and lactation: MedlinePlus (NLM) advises avoidance; no established safety data in either population
- Dose-dependent GI adverse effects (nausea, vomiting, diarrhea) are the most common reported effects; generally reduced by taking with food or using enteric-coated formulations
What we make of it
The pharmacology is right; the source is a narrative review with no pooled data.
The detail
Bypassing the rate-limiting step to serotonin is accurate pharmacology. The paper we cite is a literature review rather than an analysis with numbers behind it.