Arginine pyroglutamate is the L-arginine salt of pyroglutamic acid. It is also known as pirglutargine and arginine pidolate. It is represented by the following chemical structure:
Arginine pyroglutamate is a delivery form of pyroglutamate. Pyroglutamate is formed in the body by the cyclization of the amino acid glutamic acid and is found naturally in plant and animal products, including the brain. Pyroglutamate is also known as 2-oxo-pyrrolidone carboxylic acid or PCA and 5-oxoproline. Pyroglutamate is an intermediate of the gamma-glutamyl cycle of glutathione synthesis and degradation.
Arginine pyroglutamate, which is comprised of the amino acid L-arginine and the imino acid pyroglutamate, is a water-soluble substance.
Actions & Pharmacology
Arginine pyroglutamate is reputed to have cognition-enhancing activity. The activity is attributed to pyroglutamate.
Mechanism of Action
Since the action of arginine pyroglutamate is unclear, its mechanism of action is entirely speculative. However, pyroglutamate is structurally related to the drug piracetam, and more is known about piracetam's activity. Piracetam belongs to a class of drugs known as nootropics. The term ""nootropic,'' from the Greek, means ""acting on the mind.'' Piracetam, like pyroglutamate, is a pyrrolidone. Piracetam and related nootropics facilitate learning and memory in animal models, although human studies give mixed results except perhaps in dyslexia.
The effects of piracetam are thought to be mediated through effects on membrane fluidity in the brain. Further, some pyrrolidone-nootropic agents appear to interact with metabotropic glutamate receptors. It is not known whether pyroglutamate has any of these activities.
Little is known in detail about the pharmacokinetics of arginine pyroglutamate. Arginine pyroglutamate gets absorbed across the small intestine and is transported by the portal circulation to the liver, where both L-arginine and pyroglutamate enter into various metabolic pathways. Some pyroglutamate appears to pass into the brain.
Indications & Usage
Arginine pyroglutamate may help improve cognition (e.g. verbal memory) in the aged, though more research is required to confirm this.
There are no known reports of overdosage.
The usual recommended dose is 500 to 1000 milligrams daily. A 500 milligram dose delivers about 150 milligrams of L-arginine and about 350 milligrams of pyroglutamate.
LiteratureBarone D, Spignal G. Investigations on the binding properties of the nootropic agent pyroglutamic acid. Drugs Exp Clin Res. 1990; 16:85-99.Drago F, Valerio C, D'Agata V, et al. Pyroglutamic acid improves learning and memory capacities in old rats. Funct Neurol. 1988; 3:137-143.Moos WH, Hershenson FM. Potential therapeutic strategies for senile cognitive disorders. Drug News Perspect. 1989; 2:397-409.Provenzano PM, Brucato A, Gianguzza S, et al. Chemistry and pharmacology of arginine pyroglutamate. Analysis of its effects on the CNS. Arzneimittelforschung. 1977; 27:1553-1557.Sinforiani E, Trucco M, Cavalline A, et al. Reversibility of cognitive disorders among chronic alcoholics in phases of withdrawal. Effect of arginine pyroglutamate. Minerva Psichiatr. 1985; 26:339-346.Spignoli G, Magnani M, Giovannini MG, Pepeu G. Effect of pyroglutamic acid stereoisomers on ECS and scopalamine-induced memory disruption and brain acetylcholine levels in the rat. Pharmacol Res Commun. 1987; 19:901-912.
Research & Summary
The primary claim made for this arginine salt of pyroglutamic acid relates to cognitive enhancement. It is asserted by some that this substance can help overcome memory defects induced by alcohol abuse and in those with some forms of dementia. Some use the supplement in Italy to treat alcoholism, senility and mental retardation. While such sweeping use is unwarranted based on current findings, there are data that suggest a cognitive-enhancing role for arginine pyroglutamate, though how significant a role is far from established. Some animal studies show that the substance has positive effects in cortical and cholinergic mechanisms and that it has cognition-enhancing properties. And in one double-blind study of aged human subjects, verbal memory was said to be improved in those taking arginine pyroglutamate compared with controls who received placebo.
Contraindications, Precautions & Adverse Reactions
Known hypersensitivity to an arginine pyroglutamate-containing product.
Children, pregnant women and nursing mothers should avoid taking arginine pyroglutamate supplements.
Arginine pyroglutamate is generally well tolerated. Minor gastrointestinal complaints have been noted.