LArginin

L-arginine is an α-amino acid used in the biosynthesis of proteins. It is one of the 20 standard amino acids and is generally designated in the L-configuration, which is the form used by human cells. In humans, arginine is considered conditionally essential: it is normally synthesized in sufficient amounts, but rapid growth, illness, or injury can increase the need beyond endogenous production.

In metabolism, most arginine is processed in the urea cycle, where it is cleaved to ornithine and urea, helping to remove ammonia from the body. Arginine is also a precursor of nitric oxide, produced by nitric oxide synthase, a signaling molecule that promotes vasodilation and blood flow. Additionally, arginine contributes to the synthesis of polyamines and proline, supporting cell growth and collagen production.

Diet and supplementation: L-arginine occurs in protein-rich foods such as meat, fish, dairy, eggs, legumes, and nuts. It can be taken as a dietary supplement, often marketed to enhance nitric oxide production, exercise performance, or cardiovascular function. Evidence for clinical benefits varies by condition; robust improvements in healthy individuals are not consistently demonstrated.

Safety and interactions: normal dietary intakes are generally safe for most people. High-dose supplements can cause gastrointestinal upset or hypotension and may interact with nitrates or erectile dysfunction medications. Cautions include possible effects on herpes simplex virus replication and in certain medical conditions; use under medical supervision is advised during pregnancy, nursing, or illness.