Has anyone researched C4 pre-workout? If so, have there been any studies that reveal the safety of the product? ADVERTISEMENT 858 viewsDecember 7, 2012 0 Stacey0 December 7, 2012 0 Comments 9 Answers ActiveVotedNewestOldest 0 Sue0 Posted 0 Comments You may want to do a basic google search on studies conducted. There are very loose guidelines on most non regulated items. You are viewing 1 out of 9 answers, click here to view all answers. Register or Login