Maca for Male Infertility
Maca has not been shown to reliably improve male fertility: the best available pooled evidence found no statistically significant effect on sperm concentration, and the overall data are too small and conflicting to support its use for male infertility.
Why this grade7-layer evidence engine
This claim is graded Weak (Tier C) because, although a few small trials hint at benefit, the highest-quality evidence does not hold up. A 2022 systematic review and meta-analysis pooling five randomized trials found no significant improvement in sperm concentration versus placebo (WMD 2.22, 95% CI -2.94 to 7.37, p=0.4) and only mixed effects on motility (PMID 36110519).
The underlying trials are small and contradict one another. One double-blind RCT (n=69) did report a significant rise in sperm concentration (p=0.011) but no change in motility, morphology, or semen volume (PMID 32654242). Against this, a trial in infertile men (n=50) found placebo numerically outperformed maca and that free testosterone actually fell on maca (PMID 34585449), while a 20-man pilot showed only nonsignificant trends (PMID 26421049). An often-cited 2001 report was an uncontrolled cohort of just 9 men (PMID 11753476).
Regulators add caution rather than support. The US FDA found that 'Peru Maca' products were spiked with hidden sildenafil (the active drug in Viagra) and advised consumers not to use them, and major health bodies such as the NHS and WHO do not address maca for fertility at all. Hormone levels were unchanged across trials, so no clear mechanism supports an effect.
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 = 0.625
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高階證據未達主導 (0 positive vs 1 negative)，由 raw_score 決定
- tier_strict_requirement_check — | B→C 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