There are varying opinions on this, and there is no conclusive proof that creatine is significantly harmful to the body. What we do know is that as a supplement, it can, over time put a greater strain on the renal system (kidneys and liver), and leave residual deposits therein. We also know that these deposits dissapate with the cessation of use.
Many of the scare stories surrounding creatine came out when its use was in infancy. As always, some bodybuilders decided that if 5grm doses were shown to be effective, then 20grm doses must
be 4 times as effective
. Abuse of any substance,even including vitamins and minerals can be dangerous to your health.
Other factors that muddy the waters on these stories are that some competetive bodybuilders saw creatine as a way to maintain size and volume pre contest. This meant taking a substance that worked the renal system, at a time when it was under immense strain from dehydration and starvation toxins, not to mention residual impact of steroid abuse, so could easily be seen as the straw that broke the camels back.
if you eat clean, train hard, and choose to take creatine, then to put it in perspective, your liver and kidneys will be in far better shape than the guy who ties one down in his local bar every friday night.
Thousands of people every month are diagnosed with alcohol related organ damage, yet i bet you still have a glass of wine with your meal ocasionaly, and indeed, 1 small glass of wine or beer per day has been proven to not only be good for the heart, but is now being linked to positive effects on the risks of certain cancers.
As with everything, the body interperates a substance as good or bad in relation to use or abuse.
I dont use creatine because I found it simply doesnt work well for me so is a waste of time and money, but there is no medical evidence that would lead me to believe I damaged my health trying it to find out.