Guys I started to do some research into this issue and ran across this post because I've been going through the exact same thing with creatine affecting my lower back. I took it for years on and off and it worked great with all the benefits and for about a year now I can take it for about one week at 5g a day and then my lower back is in pain and it's a dull aggravating pain that makes me feel like crawling out of my skin. I can't sit at my desk at work for more than fifteen minutes without being so aggravated I have to stand. I was in a world of hurt for months until I figured out that Creatine was affecting me and when I stop I feel great after about two weeks but when I go back on the creatine it's misery at its finest, so I don't even mess with it anymore. It's a real issue so I wanted to give my experience to help get others to realize that this is a real issue for some of us. peace