Cellucor C4 is one of the most iconic, if not the most iconic pre workout of all time. Everybody's first pre workout is C4! C4 yields 150mg of caffeine per serving and some of the best tasting flavors on the market. C4 has just enough kick and performance to get you through your workouts but not so much that you won't be able to fall asleep at night. When To Take Cellucor C4 You should take C4 about 15-30 minutes prior to a training session. Who Can Take Cellucor C4 Both men and women can take C4 as their pre workout. Their is nothing gender specific about the product.