Citrulline Shown to Promote Lean Muscle Growth


American Journal Physiology Endocrinology Metabolism, 291: E582-E586, 2006

Citrulline is a nonessential amino add made in the liver during the urea cycle (important for eliminating ammonia, a toxic poison), Citrulline may be the next super supplement because it promotes nitric oxide production (important for blood flow control in the body) and stimulates protein synthesis. It may be particularly valuable as a supplement for older adults who often suffer from malnutrition and muscle wasting. French researchers in a study on malnourished rats- found that citrulline supplementation promoted muscle protein synthesis.

In older adults, amino acids often accumulate in the spleen (blood storage organ), which limits their availability for protein synthesis throughout the body. Citrulline isn't processed by the liver, so its nitrogen can be used to make amino acids that are critical for muscle protein synthesis. It's not known whether these results apply to healthy bodybuilders.

The effective dose appears to be greater than 400 mg/day.

Citrulline is a Powerful Arginine Builder. Nitric oxide (NO) is one of the newest and most exciting topics in medicine and physiology. NO controls I i blood flow at the tissue level and is vital for sexual function, fuel and hormone delivery to muscles, tissue oxygenation and general energy levels. The body makes nitric oxide from oxygen and the amino acid arginine. Many supplement companies sell nitric oxide supplements that mainly contain arginine.

The body also makes NO from a nonessential amino acid (doesn't need to be consumed in the diet) called citrulline. Canadian researchers- in a study on pigs- found that citrulline was very effective for increasing arginine levels. They concluded that citrulline formation or availability limited arginine synthesis. Arginine is critical for the production of nitric oxide. Citrulline may be an important supplement for maximizing the blood vessel control and metabolic health.

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