I guess im just like alot of other people who are always looking for an extra 'edge' for my high intensity workouts...when i found this i thought ,ok its got guarana which is stronger than caffeine and its got alot of arginine , which supports nitric oxide production, which helps to dilate blood vessels, allowing more blood to flow to muscles,,, also known for helping dudes with erectile dysfunction. Its also safe, by that i mean it does not have any artificial sweetners like aspartame or sucralose,, which are all harmful themselves,,,, it tastes great, but it does have a bit of sugar, adding to its 60 calorie per serving. I have had drinks with guarana and know that its very effective in giving you an extra boost,,, but for some reason this punch doesnt do it. I have even tried doubling the serving, but thats almost 120 calories of just sugar,,, so i dont like that idea,,, although some research claims that some sugar is good to help produce insulin which will help the other supplements like creatine, etc to be absorbed during a pre-workout drink. Anyway, i've been using it for close to 2 weeks, also mixing it with a scoop of protein powder,, and im still waiting for it to 'kick in'. Not expecting to become the hulk but at least it should have felt like drinking a cup of coffee,,,, which to me so far is one of the BEST pre-workout drinks especially if mixed into a protein shake. Like i said, i know that guarana does work,,, there is a drink called HI-BALL that has it along with stuff like taurine etc, and NO SUGAR or FAKE SUGAR,,, its a carbonated drink with a bit of fruit flavor and comes in a small 8oz bottle and this thing PACKS A PUNCH!!! its bitter but it proved to me that guarana DOES WORK!! so why this one doesnt, i dont know,, maybe the doses of active ingredients are minimal. I will do more research on that and submit it here. Keep in mind that nothing without caloric value like caffeine, guarana etc, can GIVE you energy,,, they are stimulants,, so they only help you to access the energy you already have. So to avoid any after effects, its always good to cycle them,,, like make sure only use them on your workout days, and even then only on hi-intensity days so that your body doesnt build an immunity to the effects. Also, always take stimulants on an empty stomach. So for a good buzz, stick with coffee!!