Legacy AI grade · Sources dated 2026-06-01. Not expert reviewed. Coverage is limited to the listed sources. About the new summary workflow
Tongkat Ali for Male Infertility
Tongkat ali (Eurycoma longifolia) shows promising but weak, preliminary evidence for male infertility: small early trials report improvements in sperm parameters, but no adequately controlled study has demonstrated higher pregnancy or live-birth rates, and real safety concerns exist. It should not be relied on as a fertility treatment.
Why this grade7-layer evidence engine
This intervention earns a Weak (Grade C) rating because the human evidence is small, heterogeneous, and silent on the outcomes that matter most. The largest fertility trial (PMID 20348942, n=350) was open-label with no placebo arm and only 75 men completing a cycle, so its reported gains in all semen parameters and 14.7% spontaneous-pregnancy figure cannot be attributed to the extract. The one true double-blind RCT (PMID 23243445, n=109) was powered for quality-of-life endpoints and reported +44.4% sperm motility and +18.2% semen volume only as secondary within-group changes, with no pregnancy outcomes.
Higher-tier syntheses do not close the gap. A narrative systematic review (PMID 28259255) found most included studies favorable but pooled no effect sizes, and the only meta-analysis (PMID 36013514) pools serum testosterone (SMD 1.352, 95% CI 0.565-2.138), not fertility or semen quality. An in-vitro study (PMID 22332826) found the extract neutral on sperm at therapeutic concentrations. No clinic or guideline body (Mayo, Cleveland, Harvard, NIH ODS, AUA/ASRM) endorses it by name for infertility.
Safety and regulatory signals also weigh on the grade. The US FDA/OPSS notes products contaminated with heavy metals such as lead and mercury and that human safety is not fully established; the EU EFSA refused a novel-food application, concluding the root extract has potential to induce DNA damage. The bottom line: tongkat ali may modestly affect semen markers, but it is unproven for achieving pregnancy and carries contamination and genotoxicity concerns.
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 = 0.472
- 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