Vascular tone governs nutrient delivery to working muscle and reproductive tissue, yet nitric-oxide synthesis declines with age and stress. Restoring endothelial flexibility elevates stamina, blood-flow–dependent performance, and erectile quality. Arginine and citrulline supply the direct substrates for endothelial NOS, while Tribulus, DHEA, and Big Libido boost androgen signaling that naturally up-regulates NO production. NAC, magnesium, boron, and adaptogenic ashwagandha mop up peroxynitrite and recycle tetrahydrobiopterin, locking in a sustained vasodilatory response.