More on creatine. Not specific on Parkinson's, But goes in to dosage and some of the research on it for anyone interested.

We have been taking some in our coffee in the morning but probably very low dose. Maybe a half gram. I need to weigh the little scoop and see.

https://www.youtube.com/watch?v=Ho7_wrS6Lb8&t=317s  #mce_temp_url#    

Hasn't killed us yet anyway.

Edit: I guess we have been taking 5 grams = 1 scoop. So much for my estimations!  
Not promoting this at all. Just what we bought for first time purchase.
In case anyone is interested. Been taking it almost three weeks at morning coffee.
https://www.amazon.com/dp/B0DX7846R5?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1 #mce_temp_url#