Use of carnitine therapy in selected cases of male factor infertility: a double-blind crossover trial

Objective To determine the efficacy of L-carnitine therapy in selected cases of male factor infertility. Design Placebo-controlled, double-blind, crossover trial. Setting University tertiary referral center. Patient(s) One hundred infertile patients (ages 20–40 years) with the following baseline sperm selection criteria: concentration, 10–20 × 10 6 /mL; total motility, 10%–30%; forward motility, Intervention(s) Patients underwent L-carnitine therapy 2 g/day or placebo; the study design was 2 months of washout, 2 months of therapy/placebo, 2 months of washout, and 2 months placebo/therapy. Main outcome measure(s) Variation in sperm parameters used in the patients selection criteria, in particular, sperm motility. Result(s) Excluding outliers, a statistically significant improvement in semen quality, greater than after the placebo cycle, was seen after the L-carnitine therapy for sperm concentration and total and forward sperm motility. The increase in forward sperm motility was more significant in those patients with lower initial values, i.e., 6 or 6 of forward motile sperm/ejaculate or sperm/mL. Conclusion(s) Based on a controlled study of efficacy, L-carnitine therapy was effective in increasing semen quality, especially in groups with lower baseline levels. However, these results need to be confirmed by larger clinical trials and in vitro studies.