I train and coach endurance athletes and I have seen all of their performances improve using this product. It works especially well for very long endurance competitions like Ironman triathlons and 50-100 mile trail running races. The product takes about 1 hour to get into the body and start being effective. This product is the best B vitamin complex I have found and is assimilated very well into the body where many are not. It then naturally boosts the metabolic and energy processes in the body. It will also do these wonderful things for non competitive people. As I have seen improvements in energy in all people that use the product. If you think the product is not working for you, it probably means you are very difficient in B vitamins and so need to take more and keep taking them for a while to build up. I have many people take this first thing in the morning to wake up and get going without having to drug themselves with 300 mg of caffeine in coffee. You may notice a yellow phosphorescent glow in your urine often as excess is excreted. This is OK and does not mean you are dehydrated.