From the Guidelines
L-carnitine supplementation may have a positive effect on sperm count and quality, but the current evidence is of low quality and insufficient to make a definitive recommendation. When considering the use of L-carnitine for improving sperm count, it is essential to weigh the potential benefits against the lack of high-quality evidence supporting its effectiveness 1. The available data suggest that antioxidant treatment, including L-carnitine, may improve semen quality and/or fertility by reducing oxidative stress and increasing total antioxidant capacity 1. However, the heterogeneity of the selected studies and the poor methodological quality of most research in this area make it challenging to draw robust conclusions 1. Some studies have reported improvements in semen parameters, such as sperm motility, after antioxidant therapy, but further detailed studies are required to confirm these findings 1. In the context of real-life clinical medicine, a cautious approach would be to consider L-carnitine supplementation as a potential adjunctive therapy for men with fertility issues, but only under the guidance of a healthcare provider and in conjunction with other lifestyle changes and evidence-based treatments. Key considerations for L-carnitine supplementation include:
- Dosage: Typically 2-3 grams daily, divided into 2-3 doses
- Duration: At least 3-6 months to see potential benefits
- Form: Available as oral supplements in various forms, including L-carnitine, acetyl-L-carnitine, and propionyl-L-carnitine
- Administration: Take with meals to improve absorption and reduce potential gastrointestinal side effects
- Safety: Generally considered safe, but consult with a healthcare provider before starting supplementation, especially if you have existing health conditions or are taking medications.
From the Research
L-Carnitine and Sperm Count
- L-Carnitine has been shown to improve sperm concentration and total sperm counts among men with astheno- or oligoasthenozoospermia, with a total daily amount of at least 3 g per day 2.
- A review of in vitro studies, pre-clinical studies, and investigations involving infertile men suggests that L-Carnitine can positively impact male fertility, even at a relatively low dose of 2 g/day, by enhancing sperm parameters, regulating hormone levels, and reducing ROS levels 3.
- However, a systematic review and meta-analysis found that carnitine supplementation significantly improves total sperm motility, progressive sperm motility, and sperm morphology, but has no effect on sperm concentration or clinical pregnancy rate 4.
- Another study found that L-Carnitine can effectively elevate sperm acrosin activity in male infertility patients, particularly in those with asthenozoospermia, and improve sperm concentration in patients with oligozoospermia 5.
- A comparative study found that a combination of eight micronutrients, including L-Carnitine, has a better effect on sperm density and motility compared to L-Carnitine alone 6.