High5 isotonic drink powder 2kgisotonic is a new generation of sports drink in hot conditions when sweat rates are high athletes often prefer a weaker mixed sports drink with a lower carbohydrate concentration which they then consume in higher volumes isotonic is the same formulation as energysource except that it has a reduced carbohydrate content when mixed as directed the carbohydrate in isotonic is 21 fructose with electrolytes research suggests that you should consume a maximum o