L-citrulline May Improve Performance in Cyclists

L-citrulline is an amino acid that helps increase production of nitric oxide, which studies have shown to promote vascular dilation and improve oxygen and blood circulation. A recent study suggests that taking supplements of L-citrulline may improve performance by as much as 1.5% in professional cyclists.

Participants in the study included 22 trained athletes who were given either 2.4 grams of L-citrulline or a placebo daily for eight days. On the eighth day, the men all performed a 2.8 mile time trial one hour after taking the last dose.

The researchers noted that the L-citrulline group finished the time trial an average of nine seconds or 1.5% faster than the placebo group. They also had a 2% greater power output than the placebo group, as well as significantly improved subjective feelings of muscle fatigue and concentration. No changes were noted in changes in oxygen consumption.

Researchers from Kyowa Hakko and Kitasato University conducted the study. It was published on February 19, 2016, in the Journal of International Society of Sports Nutrition.

Recent studies suggest that L-citrulline has antioxidant properties that could be useful in combating hypertension, heart failure, and atherosclerosis. In addition to supplements, L-citrulluine is also found in watermelons, other melons, squash, cucumbers, and pumpkins.