L-carnitine / L-acetyl-carnitine
The verdict
Promising for sperm motility/morphology in men with idiopathic infertility, but few trials, high heterogeneity, low-quality evidence.
An amino-acid derivative marketed for sperm motility; a common ingredient in Indian OTC male-fertility products.
What the evidence shows
Systematic reviews (~8 RCTs vs. placebo): significant improvement in sperm concentration, total motility, forward motility, normal morphology, and pregnancy rate — but few trials, high heterogeneity, low-quality evidence overall. Most effective reported in severe idiopathic infertility.
Evidence tier
Non-Cochrane evidence🟡 Smaller systematic reviews/meta-analyses or RCTs exist, no Cochrane-grade synthesis. Emerging, not proven.
Sources
Take this further
Last reviewed .