The glycemic index, glycaemic index, or GI is really a measure for this effects of carbohydrates on blood sugar levels. Carbohydrates that reduce quickly during digestion and release glucose rapidly into the bloodstream have a high GI; car…

And finally we have C4 Extreme from Cellucor. Still a fairly "young" pre-workout but vendors have very popular since its release. It gives users about 135mg of caffeine per single scoop, which can be a nice sized dose pertaining to just be…