L-arginine with the chemical molecular formula C6H14N4O2 is one of a total of 20 proteinogenic amino acids, i.e. it is incorporated into proteins. The name is derived from argentum (Latin for silver), because the amino acid was first extracted from horn substance as a silver salt at the end of the 19th century. The basic amino acid L-arginine is semi-essential. It is synthesized by the organism through the urea cycle, but not in sufficient quantities during the growth phase, in stressful situations, during heavier physical strain (sports) and in certain diseases. In these cases, the body is dependent on a supply of the amino acid through food or dietary supplements in the form of capsules or tablets.
What are the functions of L-arginine?
In addition to numerous functions in the metabolism, one of the most important tasks of L-arginine is the delivery of the messenger NO (nitric oxide). The neurotransmitter NO induces the synthesis of an enzyme that causes the smooth muscles in the blood vessels to relax, resulting in a blood pressure lowering effect. The effect of vascular relaxation also acts as a sexual enhancer, because an erection only occurs when the tiny ring muscles that surround and virtually clamp the arteries of the erectile tissue relax. The blood can flow into the corpora cavernosa when the arterial ring muscles are relaxed and cause an erekeion.
L-arginine also functions as a metabolite in the urea cycle, in which nitrogen compounds are first broken down to ammonia via a complex reaction cascade and then converted to urea, which is excreted by the kidneys. Via the release of the growth hormones prolactin and glucagon, L-arginine indirectly increases muscle building and supports the breakdown of lipids, thus counteracting heavy fat storage.
How can the body be supplied with L-arginine?
In order to cover the daily requirement of L-arginine of approx. 3,000 to 5,000 mg per day, the body’s own synthesis within the urea cycle is not sufficient in most cases. The body is therefore usually dependent on a supply of the amino acid through food or dietary supplements in the form of capsules or tablets. Foods that provide high levels of L-arginine include almost all types of nuts, soybeans, legumes, certain types of fish and poultry. The L-arginine content is 1,000 – 2,800 mg per 100 g of the food. Pumpkin seeds even have a content of about 5,800 mg of L-arginine per 100 g. An additional supply of L-arginine can also be provided by dietary supplements in the form of capsules or tablets.
Areas of application and dosage of L-arginine
The most important areas of application for a dietary supply of L-arginine are:
– Support of muscle building in bodybuilding
– Strengthening of the immune system (stress phases, injuries, operations, etc.)
– Support of insulin secretion in diabetes, type II
– Prevention of arteriosclerosis
– support in male erectile dysfunction (in combination with pine bark extract)
– Improvement of blood circulation (e.g. in case of tinnitus)
– Support of blood pressure lowering agents
L-arginine cannot be stored in its pure form and is therefore usually offered as L-arginine hydrochloride (HCL), which can be easily converted by the body into its bioactive form. To enable reliable dosing, the label on the packaging should indicate how much pure L-arginine is involved per capsule or tablet.
Dosage depends on dietary habits and life circumstances such as stress, illness, physical exertion, etc. Daily intake of 2,000 mg (normal load) to 5,000 mg (high load) is within the normal range.