Updated: Jul 10, 2020
L-citrulline is a naturally occurring amino acid. It is found in some foods like watermelons and is also produced naturally by the body.
L-citrulline is used by mouth for heart failure and improving athletic performance. It is also used for sickle cell disease, erectile dysfunction, high blood pressure in the lungs, and many other conditions. But there is limited scientific research to support these other uses.
L-citrulline is a naturally occurring amino acid found in food, such as watermelon. It is also made naturally in the body. The body changes L-citrulline into another amino acid called L-arginine and also to a chemical called nitric oxide.
L-citrulline might help increase the supply of ingredients the body needs to make certain proteins. It might also help open up veins and arteries to improve blood flow and reduce blood pressure.
Taking L-citrulline by mouth might be effective for improving some types of exercise performance when taken for up to 7 days. L-citrulline may help some athletes work harder, lift weights longer, and go faster on an exercise bike. But it does not seem to help people run for longer distances. Also, taking L-citrulline for up to 8 weeks does not seem to increase muscle size or strength.
Doses if taken orally:
For athletic performance: 2.4 grams or 5 grams daily for 7 days. A single dose of 8 grams just before exercise has also been used. L-citrulline maleate 2 grams daily for up to 8 weeks has also been used.
For heart failure: 3 grams daily for 2-4 months.