A good vitamin C supplement I would recommend trying would be Altrient C. I am a CrossFit athlete and heavily rely on vitamin-C to boost my energy. Altrient™ C is a proprietary high-performance vitamin C formula with a Liposome Encapsulated Delivery (LED) system that puts more usable vitamin C right where your body needs it most. More than any other oral vitamin C supplement on the market. Ever since I have started using it I have seen a significant boost to my workouts. Another highly regarded CrossFit athlete Cheryl Brost is an advocate of Altrient C as well and has had nothing but good things to say about it. Check out there website, Facebook page, or Twitter to get more info if you're interested.