What is Isotonix? Isotonix is a trademarked brand name for Market America’s Isotonix Vitamins line. Isotonix refers to the Isotonic delivery system in which Isotonix Vitamins deliver nutrients via an isotonic solution. Confused yet? Lets make it easy for you, watch the video below. What Are Isotonix Vitamins? So now you know what Isotonix means, Continue Reading