Big effect
L-Carnitine showed a massive effect on sperm motility in a meta-analysis — but only for men with unexplained infertility, not the general population.
This is one of the first systematic reviews to single out L-carnitine as the top performer for progressive sperm motility with a remarkably large effect size, but the finding is based on a narrow clinical population and the dose used wasn't specified — so it's a promising signal, not a settled recommendation.
In men diagnosed with unexplained infertility, L-carnitine outperformed other supplements in improving forward-moving sperm, a key factor for natural conception. The effect was statistically significant and unusually large, but the study didn't specify the dose, and results may not apply to men without diagnosed infertility. This is early evidence in a small research area — useful for awareness, not for action without your doctor.
Where this fits in the evidence
This is among the first studies we've indexed on L-Carnitine for Improved Progressive Sperm Motility — treat it as an early signal until more research accumulates.
The study
- Systematic Review
- 2025-08-14
- Reproductive sciences (Thousand Oaks, Calif.)
This is a plain-language summary of a research finding, not medical advice. Pillser surfaces research signals to help you decide what's worth investigating — always consult a qualified professional before changing what you take.