Reviewed on 6/11/2021
Other Name(s):

Chlorhydrate d'Ornithine, L-Ornithine, L-Ornithine HCl, L-Ornithine Hydrochloride, L-5-aminorvaline, L-2,5-diaminovaleric acid, Ornithine HCl, Ornitina.


Ornithine is a chemical called an amino acid. It is made in the body. It can also be made in a laboratory. People use it as a medicine.

Ornithine is used for improving athletic performance, reducing glutamine poisoning in the treatment of a brain condition due to liver disease (hepatic encephalopathy), and for wound healing.

Don't confuse ornithine with ornithine alpha-ketoglutarate (OKG).

How does work?

It's not known how ornithine might work for medical uses.


Possibly Effective for...

  • Brain complications caused by liver disease (hepatic encephalopathy). Most research suggests that infusing L-ornithine-L-aspartate intravenously (by IV) or taking L-ornithine-L-aspartate by mouth improves ammonia levels and disease status in people with hepatic encephalopathy.

Insufficient Evidence to Rate Effectiveness for...

  • Athletic performance. Early research suggests that taking ornithine by mouth might reduce fatigue and improve measures of athletic performance such as speed, strength, and power in some people. Also, taking ornithine in combination with arginine seems to improve strength and power in male weightlifters.
  • Wound healing.
  • Other conditions.
More evidence is needed to rate the effectiveness of ornithine for these uses.


Next to red peppers, you can get the most vitamin C from ________________. See Answer

Side Effects

There isn't enough reliable information about the safety of ornithine.


Pregnancy and breast-feeding: There is not enough reliable information about the safety of taking ornithine if you are pregnant or breast-feeding. Stay on the safe side and avoid use.


The appropriate dose of ornithine depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for ornithine. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).

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Manufacturer: Twinlab. Ronkonkoma, NY.

Rees C, Oppong K, Mardini H, et al. Effect of L-Ornithine-L-Aspartate on patients with and without TIPS undergoing glutamine challenge: a double blind, placebo controlled trial. Gut 2000;47:571-4.. View abstract.