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 ®),The new USPLabs Yok3d is here and available for sale. Nitric Oxide Support. Pick up a bottle In-stock and same day shipping available.