L-carnitine speeds recovery after exercise
by Jeff S. Volek, Ph.D., R.D.
The textbook function of L-carnitine is to help transport fat into the furnace of the cell for burning. Several lines of evidence, however, point to additional beneficial effects that help speed recovery from exercise. For example, L-carnitine injected into the bloodstream reduced the amount of oxidative stress and increased blood flow. L-carnitine was shown in one animal study to increase blood flow and force production.
Studies have shown that L-carnitine has antioxidant effects that decrease production of bad superoxide anions and increase generation of potent substances that increase dilation of blood vessels such as nitric oxide and prostacyclin. In healthy men, we reported that L-carnitine supplementation (2 grams per day for 3 weeks) resulted in significantly less accumulation of stress markers in response to resistance exercise including free radical formation, tissue damage and muscle soreness.
We performed a study to validate our prior work and determine if ingesting a smaller dose of carnitine could also provide a beneficial effect. Healthy men performed a resistance exercise challenge that included five sets of squat exercises on three separate occasions. For three weeks prior to each test, subjects ingested either 1 gram of L-carnitine L-tartrate (LCLT) per day, 2 grams of LCLT per day or a placebo.
Similar to our previous work, in this new study we showed that L-carnitine supplementation was effective at reducing the acute response of several markers of biochemical stress after resistance exercise including hypoxanthine, xanthine oxidase and myglobin. In addition, perception of muscle soreness was lower after exercise with carnitine supplementation.
A novel finding was that 1 gram per day of carnitine was as effective as 2 grams per day. The findings indicate that in addition to the traditional role of L-carnitine as a fat burner, this amino acid also helps during recovery from intense exercise. Collectively, these studies point to a role of L-carnitine in mitigating the biochemical stress response to exercise and at a lower dose than previously thought.