We tried this when we first read about it helping ALS patients several years ago. We ordered the creatine powder, and dutifully took it. Our experience (yours may be different):

1. did not help our PD that we could tell in any way, and we were really hoping for improvement, any improvement in any area;

2. we got wicked muscle cramps, and I mean, worse than we had ever experienced (drinking ALOT of water helped.....but then we had issues with peeing all the time!)...the cramps stopped when we quit taking the creatine;

3. we were early in the PD journey, maybe 3-4 years post-dx, when we started trying the creatine;

4. we took it for several months, but just could not handle the muscle cramps.

That is just our experience. If you decide to try this for yourself, be watchful for the muscle cramps.