L-Citrulline Supplement – Arginine Precursor to Improve Muscle Activity

Extensively studied, citrulline offers considerable benefits for sportspeople keen to improve their performance. Like taurine, citrulline may help reduce the accumulation of ammonia in the body, so preventing cramp, soreness, and muscle fatigue.

As a precursor of arginine, citrulline also promotes the production of nitric oxide, a compound with vasodilatory effects beneficial for muscle activity. To increase nitric oxide synthesis, other arginine supplements are available such as the complex Acetyl L-Carnitine Arginate and the specific form Arginine Alpha Ketoglutarate.

What is Citrulline?

Citrulline is a non-essential amino acid which the body produces from other nutrients under the right conditions. Together with ornithine and arginine, citrulline plays a particularly important role in what is called the urea cycle, in the liver.

In the course of this cycle, the toxic ammonium ion is converted into urea. Any disturbance to this cycle – which is essential for eliminating toxic metabolites of nitrogen – can result in a lethal build-up of proteins such as ammonia in the blood. Citrulline or arginine supplements are often recommended to treat such problems. Citrulline is also a precursor of the arginine produced during this cycle.

What do Studies Show About L-Citrulline?

• Increases levels of arginine more effectively than supplementation with arginine itself and improves nitrogen balance. Citrulline is not taken up by the liver but passes freely to the kidneys where it is metabolized into arginine.
• Appears to have a beneficial effect on sickle cell anemia.
• Has a vasodilatory effect and increases nitric oxide production.
• Decreases vascular smooth muscle cell proliferation and retards the progression of atherosclerotic lesions.
• Increases the body's metabolic rate and aerobic performance and reduces muscle fatigue.
• Stimulates the immune system.
• Speeds up recovery from fatigue.

French researchers have recently shown that citrulline modulates muscle protein metabolism in old, undernourished rats. Preliminary studies suggest that it may directly stimulate protein synthesis.