creatine and glycerol increase muscle fullness more when combined

Researchers from the University of Glasgow (Scotland) found in a 2007 study that subjects who took both creatine and glycerol for seven days had nearly 40% more body fluid than a group that took just creatine, and almost 50% more fluid than a group taking just glycerol. This has important implications for hypertrophy: Muscle cell swelling stretches the muscle membrane and instigates processes that lead to long-term growth. For better muscle pumps, take 10–30 grams of glycerol with 20–32 ounces of water about one hour before workouts. Also be sure to take creatine with your pre- and postworkout shakes for a synergistic effect.