I started to use caffeine-tablets about 3 years ago. For sports reasons. At some point I also started to use them on days, when I did not do sports. That 'some point' is now about 1.5 years in the past. In the package insert it says, not to use more then 1 tablet within 24 hours. My apothecary already talked with me, that it is not good to take them over such a long period, but I usually counter her with a Tokyo University study, which says, that risk of circulation collapse steps in with about 1 to 1.2 grams of caffeine in bloodstream. She already wanted to sell me different products like drinkable Vitamin-B6, but orally taken it has a poor efficiency factor. I would have to inject that Vitamin subcutaneous into the belly, which I don't want to. 1 caffeine Tablet has 0.2 grams caffeine, water-free. On sports day, I usually take 3-4 of them. It raises the pulse and makes you active, then I make sports and that activity also raises the pulse. At one point, I suffered heavily from Caffeine-Overuse Caffeine-Overuse - Wikipedia, the free encyclopedia My apothecary then gave me Iron-Tablets to counter it, which indeed did work. I already achieved to abstain Caffeine for some weeks, but I always again end-up with buying it. I think, I am seriously addicted. When I started to take higher-dose of the caffeine-tablets, usually some parts of my body cramped, often the muscles around the jawbone. By now, my body totally adopted to Caffeine, and I only witness light-weight activity. I don't take any other stuff, except Creatine. The Caffeine tablets are pure caffeine in water-free form. I already have a bad conscience with that Caffeine use, but I don't really am able not to take them. That sucks.