ORNITHINE

Generality

Ornithine is an amino acid derivative with basic characteristics, produced by our body starting from arginine, by the intervention of the arginase enzyme with consequent production of urea.
Ornithine represents the amino acid initiator of the urea cycle, thanks to the possibility of interacting with the carbamyl-phosphate (carrier of the first amino group) to originate citrulline, which - coming out of the mitochondrial matrix - will guarantee the continuation of the cycle itself. .
This cycle, which takes place between the cytoplasm and the mitochondrial matrix of the hepatocytes, becomes particularly intense following prolonged fasting or high-protein diets, when the oxidation of amino acids becomes a very important energy source.
The intake of ornithine - which is mainly due to foods of animal origin, from meat to fish and from eggs to milk - is therefore not essential for the human body, given the presence of a metabolic pathway capable of providing for its synthesis .
In particular, casein, a protein abundant in milk, represents an "excellent source" for the extraction of ornithine, obtainable following enzymatic hydrolysis conducted at 37 ° C.

Indications

Why is ornithine used? What is it used for?

Ornithine, re-entering the urea cycle, contributes to the correct detoxification process from ammonia, the accumulation of which could seriously compromise the health of the individual.
Despite being an amino acid, ornithine is not encoded by the genetic code, but produced in the organism following partial digestion of arginine, a conditionally essential amino acid that participates in protein synthesis, and whose production in extrahepatic cells represents the primary purpose of urea cycle.
Leaving aside the conventional biochemical-nutritional role that is due to the chemical nature of this product, ornithine is becoming increasingly important in the scientific world, thanks to a series of studies that show its direct participation in various metabolic, physiological and hormonal pathways.
More precisely, preliminary studies have shown how ornithine can:

Have an anti-fatigue role: in fact, doses of 2 g / day for 7 days and 6 g / day for one day have been shown to be effective in reducing the sensation of fatigue in healthy individuals undergoing exercise, probably by improving ammonia excretion ( involved in the genesis of the feeling of fatigue);

Play an important anti-catabolic role in the treatment of serious pathologies, such as burns, severe trauma and cachexia (in this case the doses administered are much higher, up to 10 g / day), where it helps to optimize protein synthesis processes;

As a precursor of the amino acid arginine, it increases the secretion of nitric oxide, with a series of benefits both on the vascular system and indirectly on the muscles;

Together with arginine, stimulate the secretion of GH and IGF-1 following intense physical exercise: a property that is somewhat disputed and denied by various experimental evidences;

Contribute to the production of polyamines, some of which have a protective function against the intestinal barrier.

Properties and Effectiveness

What benefits has ornithine shown during the studies?

Commonly, there is a tendency to emphasize and advertise the purchase of ornithine-based products for the alleged anabolic effect associated with the administration of this amino acid and arginine.
The search for this effect, demonstrated by few studies and promptly denied by others, risks losing sight of another important effect, commonly accepted and equally important for the athlete; we are talking about the detoxifying effect.
It is in fact known to all athletes how, following intense physical exercise, perhaps protracted over time, a significant decrease in performance is observed (associated with the "accumulation of ammonia derived above all from" amino acid oxidation), which manifests itself under form of peripheral-muscular fatigue.

Several studies, considering the modest experiments currently present on ornithine and derivatives in sports, have shown how this amino acid - especially when associated with other protagonists of the urea cycle, such as arginine and citrulline - can significantly improve the excretion of ammonia, thereby reducing the feeling of fatigue.
The presence of ornithine supplements such as ornithine alpha-keto glutarate, would also justify the ergogenic action, attributable to the ornithine salt.

Dosage and method of use

How to use ornithine

The dosages proposed in the literature obviously vary according to the needs and purposes of the supplement.
In sports, the most effective and characterized ornithine dosage is that of 2 grams per day in the training session and 6 g per day on the day of the competition.
In the clinical setting, on the other hand, the anticatabolic and anticachectic effect, reserved for patients suffering from severe burns or undergoing major surgery, would have been observed at decidedly higher dosages, such as to touch the permitted limit.
In the experimental setting, the dosages used tend to increase significantly, reaching even 15 g per day, with all the side effects of the case.
Ornithine should be taken on an empty stomach in order to avoid any competitive phenomenon capable of reducing the absorption of this amino acid.
Unfortunately, there are still no significant studies, neither from a pharmacokinetic point of view, nor from a biological point of view, which can guide the professional and the user in the development of particularly effective integrative protocols.