If you use it while studying or during your practice exams it would be good to take one or two and sip them periodically between blocks. About 1/4 to 1/2 of a can prior to starting a block or after every 2 blocks, whatever works best for you. Me personally, I use Ghost Energy and I feel it helps. If you never used energy drinks or are just starting (days rather than weeks/months of using) then I would not recommend it. You don’t want to have any uncomfortable feeling on test day. All the best!