Effects of Carnitine and Coenzyme Q10 on Sperm Quality and Pregnancy Rates in Men with Unexplained Infertility: A Systematic Review and Network Meta-Analysis.

Aims: To study and explore the effects of oral Carnitine and Coenzyme Q10 on the quality of sperm and the rate of pregnancy in males with unexplained infertility.

Background: Preventing and reducing oxidative stress is essential for male infertility treatment. Antioxidants can effectively improve sperm quality and maintain sperm motility, thereby improving male fertility. At present, the most commonly used antioxidants in the clinic are carnitine and coenzyme Q10.

Design: A systematic review and network meta-analysis.

Methods: In this study, the effects of carnitine and coenzyme Q10 antioxidants on sperm quality and the rate of pregnancy in men with unexplained infertility were explored using a network meta-analysis method. The Cochrane Library, EMBASE, Web of Science and PubMed databases were searched for relevant studies. The observed indicators included semen concentration, progressive sperm motility, the rate of morphologically normal sperm and pregnancy rate.

Results: 16 pieces of literature were included after rigorous screening. L-carnitine, coenzyme Q10 and L-carnitine + acetyl-L-carnitine significantly improved sperm quality parameters compared with placebo. CoQ10 induced the highest increase in sperm concentration (SMD 2.98 [95% CI: 1.13 to 7.87]). Furthermore, L-Carnitine has the greatest improvement effect on progressive sperm motility (SMD 4.19 [95% CI: 1.60 to 10.95]).

Conclusions: CoQ10 was the most effective intervention measure for improving sperm concentration, and L-carnitine was regarded as the best treatment method for enhancing sperm motility. In the future, we need more high-quality and large-sample studies to verify the effectiveness of antioxidants in the treatment of male infertility.