5-HTP for Fibromyalgia
5-HTP may modestly ease fibromyalgia symptoms, but the case rests on two small, 30-year-old trials from a single research group with no modern replication, and no regulator or major clinic endorses it. Given documented serotonin-syndrome and historical EMS safety concerns, it should not replace proven fibromyalgia treatment.
Why this grade7-layer evidence engine
The grade is C (weak evidence) because the entire human case rests on just two old, small studies from the same Italian group: a 1990 double-blind RCT (PMID 2193835, n=50) and a 1992 90-day open-label trial (PMID 1521674, n=50). Both reported significant improvement in tender points, pain, sleep, anxiety, and fatigue, but both are rated low quality, are over 30 years old, and have never been independently replicated by a modern RCT or meta-analysis.
No authority endorses 5-HTP for fibromyalgia. NIH ODS, Mayo Clinic, Cleveland Clinic, and Harvard Health do not recommend it for this condition, and ACR/EULAR guidelines exclude it, favoring exercise, CBT, and approved drugs such as duloxetine and pregabalin. The lack of any guideline backing keeps the grade from rising above C despite a biologically plausible serotonin-precursor mechanism.
A safety-review flag applies. The FDA states it cannot determine that oral dosage forms of L-Tryptophan and related compounds such as L-5-hydroxytryptophan can be safely used as dietary supplements, reflecting the historical eosinophilia-myalgia syndrome (EMS) link, and 5-HTP carries serotonin-syndrome risk when combined with SSRIs/SNRIs, drugs commonly used in fibromyalgia, so it should not replace evidence-based care.
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 = 0.448
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 無高階證據可裁決
- 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