When I cycled off the stuff, I would feel tired and run down for about two weeks, and finally be OK. Now when I cycle off the stuff, it gets to the point I almost have to move out of the house, or risk divorce. My wife says I turn into a complete ass, holler, and gripe all the time. Of course I would tell her she was full of it, that she just didn't want me spending the cash on the creatine. So this last time I kept myself in check, and monitored myself, and how I was feeling. She was right, I did turn in to a idiot, and really felt like crap. I mark it up to me not feeling as good off the stuff, and just plain going through withdrawals or something. I would out of the blue get an idea in my head that would get me boiling, and no matter how hard I tried I would end up raising hell with someone over it....crazy. I will stay away from it from now on...or until more research by someone other that the makers of the product.