Sign Up FREE

Sign In

Remember Me

Submit a review

How-to Guides and Articles



Also known as: L-Citrulline

Highly bio-available amino acid to increases nitric oxide (NO) levels in the body, improves endurance and reduces muscle soreness.

Members don't see ads. Sign up for FREE to remove ads, and start earning free supplements!

What is L-Citrulline?

L-Citrulline is the free form version of the amino acid Citrulline. It is a non-protein amino acid (not involved in the creation of new protein structures) that is synthesized when ornithine (another amino acid) reacts with carbamoyl phosphate. This reaction takes place in the urea cycle, the process by which the body eliminates nitrogen waste. When extra citrulline is ingested via supplementation, it sends the urea cycle into overdrive absorbing the excess nitrogen the is given off by muscles before it can succumb to fatigue.

The body produces Citrulline in two ways. The first occurs when the cells lining the intestinal walls breakdown glutamine. Citrulline is also a by-product generated by the body when it converts Arginine into Nitric Oxide (NO). A number of studies have indicated that supplementing with Citrulline increases the arginine levels in the blood (even more so than with pure L-Arginine), which results in greater NO production. As you know, more nitric oxide leads to more blood flow to working muscles. This yields two noteworthy benefits: the ability to exercise for a greater amount of time before fatiguing and creating the king of all pumps!

Where Does It Come From?

Citrulline is found naturally in the flesh and rind of watermelon. Studies have shown that blood plasma levels of citrulline and arginine are both elevated when watermelon was ingested. L-citrulline can also be found in bitter melon, gourds, pumpkins, and cucumbers.

What does it do?

From an athletic performance standpoint, Citrullines most important function is to support the optimal flow of blood in the body. It accomplishes this during is its conversion to L-Arginine, which boosts Nitric Oxide levels. Nitric oxide is a cell-signaling molecule that helps regulate blood flow, vasodilation, glucose uptake, oxygen delivery, nutrient transport, and muscle growth. Greater blood and oxygen circulation in the body helps resist the onset of both physical and mental fatigue during periods of intense physical activity. This is but one of many of the functions L-Citrulline enhances in the body.

As mentioned previously, the Urea Cycle eliminates excess ammonia and nitrogen build up in the bodys tissues. Ammonia can be extremely toxic to cells and excess levels even lead to premature cell death. Heightened levels in athletes induce fatigue, limit glycogen formation and inhibit the energy cycle. L-Citrulline is an effective buffer against such ammonia accumulation. This buffering by L-Citrulline increases endurance and boosts performance both on the field and in the weight room.

Lastly, L-Citrulline increases the rate of ATP (a cells main energy source) synthesis during exercise and raises phosphocreatine (CP) recovery after exercise. Inability to generate sufficient ATP results in premature fatigue and the sensation of "hitting the wall" that many experience during high intensity exercise.

Benefits of L-Citrulline

  • Increased Nitric Oxide production

  • Improve ATP efficiency

  • Greater energy production

  • Reduced muscle soreness

  • Higher endurance

  • Improved nutrient and oxygen transport

  • Delays onset of fatigue

  • Buffers lactic acid accumulation

  • Raise Growth Hormone (GH) levels post workout

  • Proper GI system functioning


Studies show that doses of 3-4g of L-Citrulline are needed to elicit the benefits mentioned previously.


Athletes and bodybuilders are constantly searching for any and all supplements to give them a leg up on the competition. L-Citrulline can most certainly qualify as a viable candidate.

Compared to the old pump stalwart, L-arginine, citrulline is more beneficial in raising NO levels and creating a bigger and badder PUMP. Additionally, youll experience better recovery, higher levels of energy and more muscle growth. All of this adds up to some serious GAINS in the gym and on the field of competition. Stop searching for the next big thing and look to L-Citrulline as your first option!

Copyright © 2019 All rights reserved. All trademarks are property of their respective owners.
Some links may earn us advertising or sponsor fees; see our Affiliate Disclosure.