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. 2023 Apr-Jun;24(2):69–84. doi: 10.18502/jri.v24i2.12491

Table 1.

Summary of the selected studies on protective impact of L-carnitine on sperm parameters

Authors Patients Treatment Parameters Results
Lenzi et al. (2004) 60 infertile patients Groups:

  • - L-carnitine LC (2 g/day).

  • - L-acetyl-carnitine LAC (1 g/day).

  • - Placebo

 Sperm parameters (sperm concentration, motility, and morphology) Effective increase following LC and LAC treatment in sperm motility, particularly in groups who had lower baseline levels
Aliabadi et al. (2012) 30 male mice Groups:

Treatment groups:

  • -L-carnitine (3.6 mM).

  • - L-acetyl-carnitine (3.6 mM).

Positive control group:

  • - Pentoxifylline (3.6 mM)

control group

  • - Sperm motility.

  • - Chromatin quality assay

  • - Significant increment in sperm motility in groups received LC, LAC or PF.

  • - Significant improvement in sperm chromatin quality following administration of LC and LAC
Poveda et al. (2013) 60 infertile men Groups:

  • - L-carnitine (1 g pill/12 hr).

  • - Spermotrend (1 pill/8 hr).

  • - Maca extract (1g pill/12 hr).

  • - Placebo (1 pill/12 hr)

 Semen parameters (sperm count, motility, and morphology)

  • - Improvement in sperm sample in all groups.

  • - Significant increase in sperm count in group I.

  • - Improvement in sperm motility in groups II and III.

  • - No difference in normal sperm morphology percentage in all groups
Haje and Naoom (2015) 128 infertile men with idiopathic oligoasthenozoospermia (iOA) Groups:

  • - Tamoxifen (20 mg/day).

  • - L-carnitine (1000 mg/day).

  • - Tamoxifen plus L-carnitine.

  • - Placebo

  • - Semen parameters (volume, sperm concentration, motility, viability, and morphology).

  • - Pregnancy rate after ICSI

  • - Overall improvement in semen parameters in A, B, and C groups.

  • - Decrease in semen parameters after the end of treatment.

  • - Improvement in ICSI outcomes of A or C groups.

  • - Combined tamoxifen and L-carnitine results in maximum effects in iOA men
Jihad Manssor et al. (2019) Infertile patients

  • - L-carnitine (LC) 500 mg/day

 Semen parameters (volume, sperm concentration, motility, morphology, and viability)

  • - Significant increment in sperm concentration and motility.

  • - Significant reduction in dead sperms and abnormal cells
Zhang et al. (2020) 693 idiopathic Oligoasthenoteratozoospermia(iOAT)

  • - L-carnitine (LC).

  • - L-acetyl carnitine (LAC)

  • - Semen parameters (volume, sperm concentration, motility, viability, and morphology).

  • - Pregnancy rate after ICSI

  • - Significant increment in percentage of sperm total motility, forward motility, and the number of pregnancies
Wei et al. (2021) 621 idiopathic asthenozoospermic men

  • - L-carnitine/L-acetyl-carnitine (LC/LAC).

  • - N-acetylcysteine (NAC)

  • - Semen parameters (volume, sperm concentration, motility, viability, and morphology).

  • - Hormonal assay

  • - Improvement in sperm normal morphology and motility in groups received LC/LAC and NAC.

  • - LC/LAC did not have significant impacts on sperm count, semen volume, and hormonal assay