L-arginine and L(+)-Citrulline

　　L-arginine is an amino acid commonly sold in supplement form and obtained naturally in the diet. L-arginine-rich foods include plant and animal proteins, such as dairy products, meat, poultry, fish, and nuts.

 L(+)-Citrulline,372-75-8

L-citrulline(CAS.NO:372-75-8) is a nonessential amino acid that improves the flow of blood throughout the body. It also boosts the reserve of nutrients the body requires to manufacture particular proteins. Naturally-occurring in the urea cycle, L-citrulline can be taken as a nutritional supplement to aid such conditions as mental fatigue, physical fatigue, Alzheimer's disease, heart disease, and sexual dysfunction. It can also enhance the benefits of exercising and bodybuilding.　　
　　After it is produced in the human body, L-citrulline rids the body of the toxic ammonia contained in urea. L-citrulline is then converted to L-arginine, one of the most frequently occurring amino acids. From there it transforms into nitric oxide, a gas manufactured in the body that aids in vascular health and detoxification of the liver.
　　L-arginine and L-citrulline are amino acids that have a wide range of effects on your body. Both of these protein building blocks can be found naturally in foods and synthesized in your body from other sources. In fact, citrulline can be produced in your body from arginine. Arginine and citrulline can be taken as nutritional supplements for their potential health benefits and low toxicity.
    L-Arginine Dosing：Arginine is naturally found in nuts, seeds, cereals, corn, meat, and a variety of other food products. According to the Mayo Clinic, there is little evidence for a standardized dose or arginine because many different doses have been studied. A common dose of arginine supplements range between 2 to 3 g three times a day for a total of 6 to 12 g daily. In certain clinical settings, up to 20 g of arginine per day have been used to successfully treat symptoms of congestive heart failure.
    L-Citrulline Dosing：Citrulline is found most abundantly in nature in watermelons, but is also derived from the metabolism of arginine in your body. Little peer-reviewed scientific information regarding effective dosages of citrulline are available. However, a 2008 study published by the "British Journal of Nutrition" found that short-term supplementation of citrulline in 2 to 15 g doses is safe and well-tolerated. Another study published in 2002 by the "British Journal of Sports Medicine" found that 6 g per day of citrulline supplementation promoted aerobic energy production and changes in muscle metabolism in healthy subjects during exercise.