Onion Juice (Allium cepa) for Androgenetic Alopecia
There is no direct evidence that onion juice treats androgenetic alopecia (male/female-pattern baldness); the one human trial often cited for it actually studied a different condition. Until a proper trial exists, onion juice should be considered unproven for this use, not a substitute for treatments shown to work.
Why this grade7-layer evidence engine
We grade this Unverified because not a single randomized trial, cohort, or controlled study has tested onion juice against androgenetic alopecia. The one human RCT people point to (Sharquie 2002, PMID 12126069) enrolled patients with alopecia areata, an autoimmune hair-loss condition with completely different biology, and was open-label with a small sample (n=38), uneven dropout, and no replication in over 20 years. Its 86.9% regrowth result cannot be transferred to pattern baldness.
The most recent comprehensive synthesis of AGA supplements, a 2025 network meta-analysis of 19 trials in 1,658 people (PMID 41561175), did not include onion juice at all, because no eligible AGA trial exists to enter. That absence is itself telling: it confirms a genuine evidence gap rather than a positive or negative finding.
Authorities reinforce this. The US FDA lists onion only as a GRAS food and flavoring, and the WHO monograph covers traditional oral uses, neither endorses it for hair. NIH, Mayo, Cleveland Clinic, and dermatology societies are silent on it, and Harvard Health states that for inherited pattern baldness 'only minoxidil and finasteride have been proven useful.' Onion is generally safe to handle but can irritate the scalp; the real risk is relying on it instead of proven options.
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 = 0.427
- 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 — | C→U 因 scope.conflation_risk=true 且 L11 獨評較低 (B7-2 tier cap)
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status