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Carnitine and Acetyl L-Carnitine Improve Sperm Motility

Combined treatment with L-carnitine, and acetyl l-carnitine, a related chemical, appears to improve sperm motility in men with fertility problems, according to a 2004 study.

In the study, 60 infertile men between the ages of 20 and 40 years were randomly selected to take a combination of L-carnitine and acetyl l-carnitine or an inactive placebo for 6 months.

In the medical journal Fertility and Sterility, researchers at the University of Rome led by Dr. Andrea Lenzi report that 2 months after the completion of the 6-month L-Carnitine and Acetyl L-Carnitine therapy, men who took L-carnitine and acetyl l-carnitine had increases in sperm concentration, forward movement, and total movement.

The most significant improvements in sperm motility, both forward and total, were observed in men who had the lowest levels of moving sperm when the study began. The researchers note that four spontaneous pregnancies were achieved during the study by men who had taken the combination therapy.

"Combined treatment with L-carnitine and acetyl l-carnitine... was effective in increasing sperm motility, especially in groups with lower baseline levels (of moving sperm)," the authors conclude.


OBJECTIVE: To determine the efficacy of combined l-carnitine and l-acetyl-carnitine therapy in infertile males with oligo-astheno-teratozoospermia.

DESIGN: Placebo-controlled double-blind randomized trial.

SETTING: University tertiary referral center.

PATIENT(S): Sixty infertile patients (aged 20-40 years) with the following baseline sperm selection criteria: concentration, 10 to 40 x 10(6)/mL; forward motility, <15%; total motility, 10% to 40%; and atypical forms, <80%. Fifty-six patients completed the study.

INTERVENTION(S): Patients were submitted to a combined treatment of l-carnitine (2 g/d) and l-acetyl-carnitine (1 g/d) or of placebo; the study design was 2 months' wash-out, 6 months of therapy or of placebo, and 2 months' follow-up.

MAIN OUTCOME MEASURE(S): Variation in the semen parameters that were used for patient selection.

RESULT(S): Even though increases were seen in all sperm parameters after combined carnitine treatment, the most significant improvement in sperm motility (both forward and total) was present in patients who had lower initial absolute values of motile sperm (<4 x 10(6) forward or <5 x 10(6) total motile spermatozoa per ejaculate).

CONCLUSION(S): Combined treatment with l-carnitine and l-acetyl-carnitine in a controlled study of efficacy was effective in increasing sperm motility, especially in groups with lower baseline levels.


Lenzi A, Sgro P, Salacone P, Paoli D, Gilio B, Lombardo F, Santulli M, Agarwal A, Gandini L. A placebo-controlled double-blind randomized trial of the use of combined l-carnitine and l-acetyl-carnitine treatment in men with asthenozoospermia. Fertil Steril. 2004 Jun;81(6):1578-84. PMID: 15193480 [PubMed - indexed for MEDLINE]

Key concepts: carnitine, acetyl l-carnitine, male infertility, sperm motility