The amino acid ornithine is a major biochemical intermediary compound in the urea cycle. The compound also promotes the metabolism of excess body fat by prompting the release of the human growth hormone - the hormone is involved in rapid metabolization of human body fat. The metabolization of excess body fat is enhanced when the ornithine acts in concert with arginine and carnitine - both of which are also part of the urea cycle. Proper liver function and proper immune system function also depend on the activities of ornithine. Ornithine is also considered to be an amino acid, it is however, not involved in protein or enzyme formation. However, ornithine is involved in the detoxification of excess ammonia via the urea cycle and is necessary in the regeneration of damaged liver tissues. The human skin and connective tissues contain high concentrations of ornithine, the compound is thus considered very useful for healing and repairing of damaged tissues and cellular structures anywhere in the body.
The amino acid arginine undergoes conversion in the human body to form ornithine. The ornithine thus formed can in turn be converted into citrulline, proline and glutamic acid via various biochemical pathways. Children, pregnant women and nursing mothers and anyone affected at anytime by schizophrenia must not be given supplements of L-ornithine - only a physician is qualified to assess the suitability of supplementing ornithine for such patients.
Muscle building activity seems to be promoted by ornithine and arginine as they seem to increase the levels of anabolic hormones - growth promoting hormones - like insulin and mammalian growth hormone in test animals. The anabolic activity of these two compounds is still unsubstantiated in human beings and human trails using these two compounds at reasonable supplemental levels did not induce any noticeable anabolic effects. A single human trial did suggests an increased growth hormone production in the body with the use of oral ornithine supplementation at very high dosages - the average being 13 grams of the compound given to each patient daily - such doses induced a lot of side effects that affected the gastrointestinal functioning. A large increase in total lean body mass and muscular strength was reported as an after effect of supplementation in athletes following five weeks of intensive strength training on one gram a day each of the supplements arginine and ornithine - this is in contrast to athletes in the control group who took a placebo and used the same exercise regimen. Independent laboratory based confirmation is needed to find the significance of these findings in other patients.
Ornithine is found in abundance in meats and fish, in dairy products and eggs - in general it is found in all food sources rich in proteins. Ornithine at five grams is made available in the average western diet. Ornithine is mostly synthesized in the body as an intermediary in the urea cycle or as the ornithine cycle - as it is sometimes called.
A deficiency of ornithine is not likely since ornithine is produced naturally in the human body as a part of the urea cycle. It is considered non-essential in the diet, however, spurts of growth in adolescents or pregnancy in women and the after effects of severe physical trauma or malnutrition can induce a deficiency of compound within the body.
Ornithine supplements will not greatly benefit the majority of individuals as a deficiency of this compound is unlikely. Supplemental ornithine used in various human based clinical researches on ornithine, typically use several grams of the compound daily per person, and this is combined with arginine.
The use of supplemental ornithine generally produces no adverse side effects in human tests, the only exception being gastrointestinal distress and disorders at high supplemental doses of over ten grams daily.
Ornithine production in the body requires the presence of the amino acid arginine, so high levels of arginine should suggest an increase in the production of ornithine.
Supplementation should be done with care as ornithine and arginine are best supplemented together and are interconvertible in the body. Supplements of ornithine in pregnant or nursing mothers, is not recommended if not carried out under the strict supervision and consultation of a doctor. Supplements of ornithine and arginine must not be given to infants or to growing children and adolescents - unrestricted use of arginine in the growing body can induce gigantism in individuals. The potential use of any amino supplementation to correct a problem related to dwarfism in an infant or child must be discussed with a qualified health care provider. Supplements of ornithine and arginine must never be used by individuals with any known history of schizophrenia. Supplements of ornithine or arginine must not be used by individuals affected by herpes; such people must also avoid consuming foods that are rich in the amino acid arginine. Large doses of ornithine and arginine consisting of 20 or more grams are considered excessive and may induce bone and joint deformities in a person. The skin on the body can also become coarse and thickened if too much arginine is consumed over a period of several weeks even as a part of the supplemental regimen consisting of combined ornithine and arginine doses. The intake of the arginine must be lowered for the problem to correct itself over time.