Creatine will take a couple of weeks to build up in your system. You typically "load" for a week on three teaspoons a day (15 grams) and then back off to one (5 grams). However, I have found that when I did this, the results went back down. I experimented with 3 teaspoons a day, every day and eventually settled at 5 teaspoons a day. I believe my size may have something to do with this, at 5' 10'' and 250, I'm not exactly little. As I recall, liver damage can occur at dosages of around 40 grams a day.
I also rarely get off of it and have lab tests conducted twice yearly. No problems.