Ornithine is a non-essential amino acid derived from the breakdown of arginine during the citric acid cycle. It helps build muscle and reduce body fat, especially when combined with the amino acids arginine and carnitine. Ornithine is also necessary for the formation of citrulline, proline, and glutamic acid, three amino acids that help provide energy to every cell in the body. Measurement of ornithine is included in the Amino Acids, Plasma and Amino Acids, Urine tests along with 23 other amino acids.
Ornithine (Orn) is a non-essential amino acid, meaning that the body can synthesize the necessary amount. Ornithine can also be obtained from the diet. Meat, fish, dairy products, and eggs are good sources of this nutrient. Few people are deficient in ornithine unless they are extremely malnourished or have some disturbances in the citric acid cycle.
Ornithine helps remove toxic ammonia from the liver and can reduce the effects of liver cirrhosis and disorders associated with liver dysfunction. Research has also shown that ornithine aids in tissue healing and regeneration.
Ornithine is often combined with arginine and marketed as a muscle-building supplement. Laboratory studies have shown that ornithine increases levels of both insulin and growth hormone, which are needed to build and maintain muscle during intense physical training. Ornithine can also help fight muscle loss which is a normal process of aging. By helping to increase growth hormone levels, ornithine can help accelerate muscle tissue production and counteract the effects of aging. Although both arginine and ornithine help protect and build muscle mass, ornithine is generally considered to be more effective at stimulating growth hormone production than arginine.
Ornithine is also included in many commercially available sports and protein drinks. No side effects have been reported with the use of ornithine, although gastrointestinal disturbances may occur with an intake of more than 10 grams per day.