yok4dYok3D ® is the ultimate non-stimulant Nitic Oxide stimulator developed by USP Labs. The main ingredient in Yok3D ® is Inositol-stabilized Citrul Silicate (Citrul Silicate as Nitro-Rx ®), a proprietary complex of bonded arginineNon-Stim Nitric Oxide Support - USP Labs Yok3d. If you're looking to build muscle pumps and growth, all together with a stim-free formula, then USP Labs Yok3d is the supplement for you!