An amino acid your body converts toward nitric oxide.
L-Arginine is an amino acid your body uses to produce nitric oxide, the same relaxation signal beet root is aimed at.
Because blood flow matters for both energy and physical performance, L-Arginine shows up across this entire category of supplement.
The HCl (hydrochloride) form is used here, listed as one of six named ingredients rather than a stand-alone high-dose product.