Short answer: L-Lysine HCl is an amino acid studied alongside vascular health markers, including some research on arterial plaque.
Why "including some research" is a careful, honest qualifier
This phrasing acknowledges a more limited, specific research angle rather than implying broad, settled evidence for this particular ingredient.
Why this ingredient rounds out the formula's seven-ingredient list
L-Citrulline, Pine Bark Extract, Nattokinase, Magnesium Citrate, L-Lysine HCl, Vitamin K2 and Vitamin C — seven named ingredients, each with a distinct, specifically described role.
💡 Worth knowing: this ingredient's research base is narrower than L-Citrulline's more extensively studied nitric-oxide role — worth understanding this distinction.