Ornithine, an amino acid, is manufactured by the body when another amino acid, arginine, is metabolized during the production of urea (a constituent of urine).
Where is it found?
As with amino acids in general, ornithine is predominantly found in meat, fish, dairy, and eggs. Western diets typically provide 5 grams per day. The body also produces ornithine.
Ornithine has been used in connection with the following conditions (refer to the individual health concern for complete information):
| Science Rating | Health Concerns |
|---|---|
 | Liver cirrhosis (hepatic encephalopathy) (L-ornithine-L-aspartate) Recovery from illness (ornithine alpha-ketoglutarate) |
 | Athletic performance (for body composition and strength) |
 Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit. For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit. | |
Who is likely to be deficient?
Since ornithine is produced by the body, a deficiency of this nonessential amino acid is unlikely, though depletion can occur during growth or pregnancy, and after severe trauma or malnutrition.1
How much is usually taken?
Most people would not benefit from ornithine supplementation. In human research involving ornithine, 5–10 grams are typically used per day, sometimes combined with arginine.
Are there any side effects or interactions?
No side effects have been reported with the use of ornithine, except for gastrointestinal distress with intakes over 10 grams per day.
The presence of arginine is needed to produce ornithine in the body, so higher levels of this amino acid should increase ornithine production.
References
1. Zieve L. Conditional deficiencies of ornithine or arginine. J Am Coll Nutr 1986;5:167–76. [review]
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2006-09-07
