After I had taken creatine for about 4 weeks, I began to have pain in my lower abdomen. I have no evidence that it had anything to do with the creatine, but it could have. I continued to take the supplement until my 6 week cycle was finished. By the end of the cycle, I was having trouble running hard because my abdomen hurt when I tried to pick my knees up. I don't know that this had anything to do with the creatine, but it could have. The positive benefits were very obvious, however. My strength increased and I lost about 10 pounds of fat. My performance in the high jump also improved, and even though I had a bad day at nationals, I finished 6th even though everyone else that placed was at least 2 years younger than me.

My daughter had no negative side effects, gained 5 pounds, and her high jump improved from 4'10" to 5'4" in 6 weeks. No, I can't prove that it was from the creatine, but the year before she only improved 1" in the entire year. We have not yet decided whether to do this again. She does not like the taste or the amount of fluids that you need to take, but it certainly seems to improve performance. I'm not afraid of negative side effects, and whatever was causing my problems is gone now. I know for sure that explosion, power, and strength improve when using the product, and I would recommend it, at least in limited circumstances to sprinters, and jumpers.