5-HTP for Depression
5-HTP shows a possible short-term benefit over placebo for depression, but the evidence rests almost entirely on small, dated, low-quality trials, and serious safety concerns mean it cannot be recommended over established treatments. It is not a substitute for therapy or prescription antidepressants.
Why this grade7-layer evidence engine
The supportive data is thin. A Cochrane-derived 2002 review (PMID 12169147, PMID 11687048) found 5-HTP and L-tryptophan beat placebo (Peto OR 4.1, 95% CI 1.3-13.2), but only 2 of 108 located trials, totaling just 64 patients, met basic quality criteria, so the authors judged the evidence too weak to be conclusive. A 2020 meta-analysis (PMID 31504850) reported a high remission rate and a large effect (Hedges' g 1.11), yet its own authors flagged the pooled studies as methodologically weak with few placebo controls.
Regulators and clinics decline to endorse it. The US FDA states it cannot determine that 5-HTP can be safely used as a dietary supplement, and EFSA has rejected mood-related claims. The Mayo Clinic is cautious, noting some supplements may help some people but that more research on efficacy and side effects is needed, and that supplements cannot replace medical treatment.
Safety is the deciding factor. 5-HTP raises serotonin and can cause potentially dangerous serotonin syndrome when combined with SSRIs, SNRIs, or MAOIs, drugs many people with depression already take. Both Cochrane reviews also flag a possible link to the potentially fatal Eosinophilia-Myalgia Syndrome tied to contaminated tryptophan-class products. Given a weak evidence base and real harms, this earns a cautious preliminary grade with a safety review rather than a recommendation.
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditable▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.597
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (1 篇 > 0 negative)
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status