Written by Taylor Woosley, Science Writer. 3-month supplementation of an L-carnitine complex nutrient treatment (15 g/bag, twice a day) significantly improved testosterone levels (p<0.001), LH levels (p=0.009), percentage of progressive sperm motility (p<0.0001) and resulted in a higher percentage of normal sperm morphology (p=0.01) compared to the control group.
Infertility affects about 15% of the world’s population and in around 40-50% of infertile couples, a male factor underlies the problem1. Findings of a meta-analysis has shown that sperm concentration decreased by 52.4% between 1973 and 20112. Male infertility has a variety of causes, ranging from genetic mutations, lifestyle choices, medical illness, or medication3.
Oxidative stress plays a significant role in male infertility and antioxidant therapy is an effective way to scavenge excessive reactive oxygen species (ROS)4. L-carnitine, and its active form of L-acetylcarnitine, is a vital antioxidant that protects the sperm mitochondria from oxidative stress5. Additionally, coenzyme Q10 (CoQ10) possesses strong antioxidant properties involved in mitochondrial energy production, which is essential in maintaining the efficient energy system of spermatozoa and protecting their membranes from lipid peroxidation6.
Ma et al. conducted a randomized controlled trial to compare the use of L-carnitine versus CoQ10 and vitamin E on improving outcomes in men with idiopathic asthenozoospermia or teratozoospermia. The trial design followed a one-month run-in followed by a 3-month treatment. Subject inclusion consisted of adult men aged 20-40 years experiencing infertility for >1 year who were having regular sexual intercourse with females who did not have infertility. Furthermore, subjects had normal rheological characteristics of semen with normal volume and pH. Participants were randomly assigned to either the study group or control group. The study group was administered a 15 g/bag of L-carnitine complex nutrient treatment, orally, twice a day. The control group received a 10 mg tablet of CoQ10, orally, three times daily with a 100 mg tablet of vitamin E, orally, three times daily.
Subjects underwent semen analysis at baseline and 3-months after therapy with semen being obtained by masturbation after a sexual abstinence of 3-5 days. Semen analysis focused on sperm concentration, progressive sperm motility, and normal sperm morphology. A serum hormonal analysis consisting of testosterone, follicle stimulating hormone (FSH), luteinizing hormone (LH), and prolaction levels was completed at baseline and end of intervention. A student’s t-test was utilized to compare baseline and outcome data between the study and control groups.
143 subjects were included in the final analysis (n=73 in the intervention group, n=70 in the control). No statistically significant differences were noted between groups regarding serum levels of testosterone, FSH, LH, and prolactin at baseline. Significant findings of the study are as follows:
- At 3 months, serum testosterone levels increased to 4.31 ± 0.78 ng/ml in the intervention group and 3.76 ± 0.74 ng/ml in the control (p < 0.001).
- A statistically significant difference in LH levels between groups was noted (5.65 ± 1.73 mIU/ml vs. 4.88 ± 1.78 mIU/ml, p=0.009) at the end of the intervention.
- At 3 months, a statistically significant higher concentration of sperm was noted in the study group (40.51 ± 18.66 x 106/ml), compared to the control (30.3 ± 17.5 x 106/ml) (p=0.001).
- The study group experienced a significantly higher percentage of progressive sperm motility (32.29 ± 10.25%), compared to the control (25.64 ± 9.55%, p<0.0001). Furthermore, the percentage of normal sperm morphology was also significantly higher in the study group (4.15 ± 2.12%), compared to the control (3.33 ± 1.93%, p=0.01).
Results of the randomized controlled trial show that both L-carnitine and CoQ10 with vitamin E supplementation improved sperm parameters. However, only subjects in the L-carnitine group experienced significant improvements in sperm concentration, progressive motility, and normal morphology, while also having a significant increase in LH and testosterone levels. Further research using longer trial periods and studies examining clinical pregnancy rates are necessary to better comprehend the effects of L-carnitine on male idiopathic infertility.
Source: Ma, L., and Y. Sun. “Comparison of L-Carnitine vs. Coq10 and Vitamin E for idiopathic male infertility: a randomized controlled trial.” European Review for Medical & Pharmacological Sciences 26, no. 13 (2022).
Click here to read the full text study.
Posted February 22, 2024.
Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.
References:
References:
- Mahbouli S, Dupont C, Elfassy Y, Lameignère E, Levy R. Exploring the potential impact of nutritionally actionable genetic polymorphisms on idiopathic male infertility: a review of current evidence. Asian J Androl. Sep-Oct 2021;23(5):441-449. doi:10.4103/aja.aja_87_20
- Dupont C, Faure C, Daoud F, Gautier B, Czernichow S, Lévy R. Metabolic syndrome and smoking are independent risk factors of male idiopathic infertility. Basic Clin Androl. 2019;29:9. doi:10.1186/s12610-019-0090-x
- Fainberg J, Kashanian JA. Recent advances in understanding and managing male infertility. F1000Res. 2019;8doi:10.12688/f1000research.17076.1
- Dutta S, Sengupta P, Roychoudhury S, Chakravarthi S, Wang CW, Slama P. Antioxidant Paradox in Male Infertility: ‘A Blind Eye’ on Inflammation. Antioxidants (Basel, Switzerland). Jan 16 2022;11(1)doi:10.3390/antiox11010167
- Khaw SC, Wong ZZ, Anderson R, Martins da Silva S. l-carnitine and l-acetylcarnitine supplementation for idiopathic male infertility. Reprod Fertil. Jul 2020;1(1):67-81. doi:10.1530/raf-20-0037
- Salvio G, Cutini M, Ciarloni A, Giovannini L, Perrone M, Balercia G. Coenzyme Q10 and Male Infertility: A Systematic Review. Antioxidants (Basel, Switzerland). May 30 2021;10(6)doi:10.3390/antiox10060874
