What is Ornithine

Chemical Name:2,5-diaminopentanoic acid

Molecular Weight:132.16

Structrual Formula:C5H12N2O2

Nitrogen Content: 16.61%

Ornithine (1)

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).

Ornithine in Food

Ornithine can be found in meat, fish, dairy and eggs.

The presence of arginine is needed to produce ornithine in the body, so higher levels of this amino acid should increase ornithine production.

Ornithine and Hormones (334)

Animal research has suggested that ornithine, along with arginine, may promote muscle-building activity in the body by increasing levels of growth-promoting (anabolic) hormones such as insulin and growth hormone.

In clinical studies on people hospitalized for surgery, generalized infections, cancer, trauma, or burns, supplementation with ornithine alpha- ketoglutarate (OKG) has been reported to produce several beneficial effects. However, most human research does not support these claims at reasonable intake levels. One study that did demonstrate increased growth hormone with oral ornithine used very high amounts (an average of 13 grams per day) and reported many gastrointestinal side effects. One controlled study reported greater increases in lean body mass and strength after five weeks of intensive strength training in athletes taking 1 gram per day each of arginine and ornithine compared with a group doing the exercise but taking a placebo. These findings require independent confirmation.

Side Effects of Ornithine (61)

No side effects have been reported with the use of ornithine, except for gastrointestinal distress with intakes over 10 grams per day.

L-Ornithine Supplement

L-Ornithine is used as a nutritional supplement principally for its putative anabolic activity. There is little evidence to support this use. However, a derivative of L-ornithine called ornithine alpha-ketoglutarate or OKG may, under certain conditions, have immunomodulatory and anticatabolic and/or anabolic actions.

Ornithine Function (335)

Ornithine is important because it induces the release of growth hormone in the body, which in turn helps with fat metabolism. Ornithine is required for a properly functioning immune system and liver. It assists in ammonia detoxification and liver Rejuvenation. Ornithine helps healing and repairing skin and tissue and is found in both these body parts. Unsupported claims that ornithine promotes muscle building, but this has not been proven. Ornithine is helpful for people recouping after surgery and athletes may benefit from this nutrient. L-Ornithine can be changed into L-Arginine in the body and it functions similarly in growth hormone release.


  • 13) Balch, James, MD, and Phyllis Balch, CNC, Prescription for Nutritional Healing, Avery Pub., 1997.
  • 334) Gourmelen M, Donnadieu M, Schimpff RM, Lestradet H, Girard F. Effect of ornithine hydrochloride on growth hormone (HGH) plasma levels. Ann Endocrinol (Paris). 1972 Sep-Oct;33(5):526-8.
  • 61) Peter J. Garlick. The Nature of Human Hazards Associated with Excessive Intake of Amino Acids. J. Nutr. 2004 134: 1633-1639.
  • 335) Lalinde E, Sanz J, Ballesteros A, Elejabeitia J, Mesa F, Bazan A, Paloma V. Effect of L-ornithine 8-vasopressin on blood loss during liposuction. Ann Plast Surg. 1995 Jun;34(6):613-8.
  • 328) Bucci LR, Hickson JF, Wolinsky I, Pivarnik JM. Ornithine supplementation and insulin release in bodybuilders. Int J Sport Nutr 1992;2:287–91.
  • 333) Fogelholm GM, Naveri HK, Kiilavuori KT, et al. Low-dose amino acid supplementation: no effects on serum human growth hormone and insulin in male weightlifters. Int J Sport Nutr 1993;3:290–7.
  • 336) Lambert MI, Hefer JA, Millar RP, et al. Failure of commercial oral amino acid supplements to increase serum growth hormone concentrations in male body-builders. Int J Sport Nutr 1993;3:298–305.
  • 327) Bucci L, Hickson JF, Pivarnik JM, et al. Ornithine ingestion and growth hormone release in bodybuilders. Nutr Res 1990;10:239–45.
  • 332) Elam RP, Hardin DH, Sutton RA, et al. Effects of arginine and ornithine on strength, lean body mass and urinary hydroxyproline in adult males. J Sports Med Phys Fitness 1989;29:52–6.
  • 330) Cynober L. place des nouveaux substrats azotés en nutrition artificielle périopératoire de l’adulte. Nutr Clin Métabole 1995;9:113 [in French].
  • 326) Brocker P, Vellas B, Albarede JL, Poynard T. A two-centre, randomized, double-blind trial of ornithine oxoglutarate in 194 elderly, ambulatory, convalescent subjects. Age Ageing 1994;23:303–6.
  • 338) Stauch S, Kircheis G, Adler G, et al. Oral L-ornithine-L-aspartate therapy of chronic hepatic encephalopathy: results of a placebo-controlled double-blind study. J Hepatol 1998;28:856–64.
  • 329) Cynober L. Amino acid metabolism in thermal burns. JPEN J Parenter Enteral Nutr 1989;13:196–205.
  • 331) De Bandt JP, Coudray-Lucas C, Lioret N, et al. A randomized controlled trial of the influence of the mode of enteral ornithine alpha-ketoglutarate administration in burn patients. J Nutr 1998;128:563–9.
  • 339) Zieve L. Conditional deficiencies of ornithine or arginine. J Am Coll Nutr 1986;5:167–76. [review]