Ornithine is an amino acid found in the human body. It is made when the body disposes of excess nitrogen in the urine.
Ornithine has been shown to stimulate energy and growth hormone, which makes it of interest to bodybuilders. It has been used to improve performance during exercise. However, studies have shown mixed results when using ornithine hydrochloride to improve exercise performance.
Ornithine is combined with a compound called amino acid aspartate to improve liver health. Although research supports the use of ornithine for liver problems, more evidence is needed before further conclusions can be made.

Related Terms

(+)-(S)-2,5-Diaminopentanoic acid, (+)-(S)-2,5-diaminovaleric acid, amino acid, guanidinium, L-arginine, L-norvaline, L-ornithine, L-ornithine-L-aspartate, ornithine (VAN), ornithine hydrochloride, ornithinum (Latin), putrescine, (S)-ornithine, urea.

evidence table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Ammonia toxicity (poisonous blood levels of ammonia) (Grade: C)
The use of L-ornithine-L-aspartate has helped reduce harmful levels of ammonia in the body, which may help ease symptoms of liver problems. However, more evidence is needed to confirm this potential benefit.
Deficiency (ornithine deficiency) (Grade: C)
L-ornithine-L-aspartate may help people who have ornithine deficiency caused by disease. More high-quality human studies are needed before conclusions can be made.
Exercise performance (Grade: C)
Limited research suggests that ornithine in combination with other substances may improve physical performance in women, but the results are mixed. More clinical trials are needed to study the potential benefits of ornithine alone.
Hepatic encephalopathy (brain problems due to diseased liver) (Grade: C)
L-ornithine-L-aspartate has been studied to treat brain problems that occur because the liver can no longer remove toxins from the blood. This combination may improve brain function and quality of life, but more studies are needed before conclusions can be made.
Liver disease (various) (Grade: C)
L-ornithine-L-aspartate combined with other therapies has been studied in the treatment of liver diseases. Clinical trials are needed to determine the effects of ornithine alone.
Movement disorders (Grade: C)
Taking ornithine in addition to creatine supplements and avoiding arginine intake may benefit people with movement disorders. However, further research is needed.