arginine + leucine

Arginine + leucine is a combination of two amino acids, L-arginine and L-leucine, commonly used as a dietary supplement. Both are involved in protein synthesis and metabolic regulation. Arginine is a semi-essential amino acid that serves as a precursor for nitric oxide, which acts as a vasodilator to improve blood flow and has roles in hormone secretion and immune function[3][6][7]. Leucine is an essential branched-chain amino acid (BCAA) critical for muscle protein synthesis, energy regulation, growth hormone production, wound healing, and the prevention of muscle breakdown after trauma or severe stress[5]. When combined as supplements—primarily studied in animal models such as pigs—arginine plus leucine has been shown to decrease body fat weight, alter gut microbiota composition (increasing beneficial short-chain fatty acids), modulate lipid metabolism gene expression in muscle and adipose tissue, improve meat quality traits (in animals), and potentially influence insulin release[1][2][8]. The combination may have potential applications for obesity management or metabolic health; however, most evidence comes from animal studies.