So since Don's email address is posted in this thread, I thought I would ask some Mannitol questions in an email to him.

Here are my questions to Don McCammon:
Can I ask how long you have had PD and if you take Sinemet now or in the past and if it helped you? Is your brother taking mannitol and how has he done on it. And, in general, how have other people who take mantitol done. If some one who has advanced PD, will mannitol allow them to lower their Sinemet dose and also reduce on/off time and other PD problems? Testimonials would be great.

And his reply:
I am so sorry about your wife's condition. At this point I doubt she would benefit from Mannitol in that she has probably lost most if not all of her dopinergic neurons.


Don

So he has not provided any information or testimonials on his customers who he sells Mannitol to. I don't know if he ever took Sinemet and he claims it only helps with early onset PD. I was hoping for a more informative response.
When low dose naltrexone LDN was being claimed as a lifesaver 10 years ago. My wife began taking it then for 7 years. It did not help and she is at a very advanced PD stage now.