Concentrations of L-carnitine can be found in the epididymis and sperm cells of the male reproductive system. Scientists have found that L-carnitine plays a key role in sperm motility and respiration, making adequate carnitine levels essential for male fertility. Clinical research demonstrates that L-carnitine supplementation can benefit men with fertility problems. In a study published in 2005, researchers gave 30 participants with male infertility two grams of L-carnitine per day for three months. Sperm health was measured at baseline and after carnitine treatment. Results showed that participants who received L-carnitine and had normal mitochondrial function showed a significant increase in sperm motility above baseline levels.
In another study, researchers wanted to know if carnitine supplementation would reduce infertility among 60 men with low sperm counts, atypical sperm or reduced sperm motility. Participants were given two grams of L-carnitine and one gram of acetyl-L-carnitine or a placebo daily for two months. Men receiving the carnitine supplements demonstrated significantly improved sperm count, motility and form over those receiving placebo.
While athletes and sports enthusiasts have used carnitine supplements to enhance performance, little evidence exists to support the claim that carnitine supplements can enhance energy, stamina or overall athletic performance. Some studies have found, however, that carnitine supplements may help reduce muscle soreness in some athletes.
While some people claim that carnitine supplements promote weight loss, little, if any, credible scientific evidence supports this claim.
Forms and Usual Dosages
L-carnitine and acetyl-L-carnitien supplements are available as tablets, capsules and chewable wafers. Dosages of acetyl-L-carnitine used in studies on cardiovascular disease and Alzheimer’s range from 1.5 to three grams per day, with a usual dose of two grams per day. Carnitine supplements may cause nausea and vomiting, especially when taken on an empty stomach, so it’s best to take them with meals. If you have heart disease, diabetes, kidney disease, liver disease or any other serious medical condition, be sure to consult with your physician before taking a carnitine supplement.
Carnitine Fast Facts
Uses and Benefits: Carnitine supports lipid metabolism and helps maintain healthy triglyceride levels. Carnitine may also benefit people with cardiovascular disease, chronic fatigue syndrome, Alzheimer’s disease and male infertility.
Sources: The body can produce carnitine from the amino acids lysine and methionine, which are found in animal foods such as beef, pork, chicken, organ meats and dairy products. Carnitine supplements are also available in health food stores.
Special Considerations: Carnitine may cause nausea and vomiting, especially on any empty stomach, and should generally be taken with meals. People with serious health conditions, including heart disease, diabetes, kidney disease and liver disease should consult with physician before taking carnitine supplements.