I've tried it and I wouldn't advice it. Prolonged use can pretty much have you acting bipolar. It'll make you paranoid and give you insominia. Now it never got that bad for me, but for a few people I know personally. I was experimenting with supps back then. Aside from ginseng which I took daily since my teens my system is clean. The safest thing to do to increase energy besides eating healthy is getting more sleep.