L-Carnitine Supplementation: Can it Improve Your Performance?
L-carnitine is the latest supplement to become popular among athletes, fitness buffs, and even those seeking to lose weight. But does the supplement improve athletic performance or accentuate metabolic burn? Does L-carnitine live up to the hype? This article will discuss what L-carnitine is, the claims made about what supplementing with it can accomplish, and what scientific research reveals about its effects.
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What is L-carnitine?
L-carnitine is an amino acid the body creates naturally. Carnitine is also found in animal source foods including dairy products and red meat. L-carnitine supplementation has been deemed safe for human consumption and has been used for years to treat individuals who do not produce enough of the amino acid on their own due to a genetic disorder, are taking certain medications that lower the body’s natural level of L-carnitine, are undergoing dialysis due to kidney failure—the procedure depletes L-carnitine, and as a dietary replacement for vegetarians and those with other nutritional needs. L-carnitine is also used to treat numerous circulatory and heart disorders including angina and congestive heart failure.
Claims Made about L-carnitine Supplementation
As often happens with the latest in vogue supplement, L-carnitine has been credited with aiding in a wide assortment of physical problems. Scientific studies do suggest a link between L-carnitine supplement usage in the effectual treatment of hair loss in men and women. Promising research results have also been noted in the use of L-carnitine to treat physical and mental fatigue due to age. And L-carnitine has been indicated as an effective remedy for acne. Findings that have suggested L-carnitine is an effective aid in increasing metabolism, leading to weight loss and decreased waist size, have made L-carnitine supplementation particularly appealing to bodybuilders and those looking for a way to fight belly fat alike.
As Heidrun and Lohninger (2004) point out in their comprehensive literature review of investigative studies into L-carnitine supplementation for athletes, manufacturers of dietary supplements regularly make promises regarding the efficacy of a product to improve athletic performance. Claims that physiological or mental performance will increase as a result of use or that exercise recovery rates will shorten are plentiful, while evidence to back up these purported benefits are too often scarce, if not non-existent. Because converting fat into energy is one of the primary functions of L-carnitine within the human body, this form of supplementation has become increasingly popular among athletes across the sports spectrum speculating that it may have ergogenic benefits.
2014 Study into L-carnitine Supplementation in Endurance Athletes
In 2014, Orer and Guzel reported the findings of their controlled study which included 26 professional soccer players who had volunteered to participate in the double-blind research experiment. First, 12 of the athletes were administered 3 grams of L-carnitine, while the other 14 participants received a dose of 4 grams of L-carnitine. Following the administration of L-carnitine, an endurance running test was given, starting at speeds of 8 kilometers/hour, then increasing to 10 kilometers/hour. The rate of speed was constantly amplified at a rate of 1 kilometer/hour every 3 minutes until each participant voluntarily stopped running. The subjects’ heart rates were observed throughout the stress test by utilizing portable telemetric monitors. Blood was taken from the participants prior to the test and before the rate of speed was amplified, in order to measure lactate concentrations. A week later, the original test was repeated with the participants given placebos rather than L-carnitine. The study results demonstrated that when the players were given L-carnitine in dosages of 3 or 4 grams, exercise exhaustion times were prolonged in comparison to the placebo.
Additional Research Studies
It should be noted that research results into the efficacy of L-carnitine as a sports enhancing supplement have been mixed. Heidrun and Lohninger (2004) observed that while some investigative studies demonstrated a link between L-carnitine usage and enhanced athletic performance, other studies found no demonstrable advantage from taking the supplement. That said, Heidrun and Lohninger (2004) did find that the preponderance of studies did support the conclusion that L-carnitine supplementation in athletes increases optimal oxygen consumption and the resulting lessening demand for breaths suggests that using L-carnitine supplements may promote lipid metabolism. Studies have also revealed L-carnitine supplementation to be effective in substantially reducing the formation of plasma lactate during aerobic exercise. This is important because suffecient lactate clearance is vital for endurance training and sports, including running and hurdling.
Orer and Guzel (2004) also found early research studies linking L-carnitine supplementation with augmented muscle function and improved exercise workout recovery times to be compelling. While they observed that findings in these areas had also been conflicted, Orer and Guzel (2004) noted that the preponderance of research had suggested “that L-carnitine stimulates muscular metabolism by increasing turnover rates.” It was hypothesized that the post-workout restorative effects to muscle tissue could be explained by the known function L-carnitine performs in the body’s natural wound healing mechanism (Orer & Guzel, 2004).
It is interesting to note that while this literature study did find compelling evidence to suggest L-carnitine could be beneficial to athletic performance and recovery in numerous ways, acting as a “fat burner” was not one of them (Orer & Guzel, 2004). In fact, numerous experts have concluded that claims L-carnitine can increase fat metabolism rates, augment muscle mass, and decrease fat mass have no evidentiary support. Medical and sports training experts alike support the conclusion that more research is needed into L-carnitine supplementation to analyze and assess the risks and rewards of usage.
Conclusion
When contemplating trying any new supplement it is important to discuss the potential side effects with your primary care physician and a knowledgeable trainer or coach. In the case of L-carnitine, the purported benefits may be tempting to those seeking to find the competitive edge, but it must be remembered that this amino acid is used to treat serious heart and other health issues and has the potential to interact with medications you may be taking. While the research into L-carnitine use to aid athletic performance has yielded some promising results, more investigation needs to be completed.
References
Heidrun, K. & Lohninger. (2004).A. Supplementation of L-Carnitine in Athletes: Does It Make Sense?
Kraemer, W.J., Volek, J.S. & Dunn-Lewis, (1 January, 2008). C. L-Carnitine Supplementation: Influence upon Physiological Function.
Orer, G.E., & Guzel, N.A. (2014). The Effects of Acute L-carnitine Supplementation on Endurance Performance of Athletes.
WebMD. (2018). L-carnitine.
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