Another pwp has tried it and had success. Others have tried and didn't help. There are just individual case reports, no formal trials to determine if it works or if this is just placebo effect (we pwp REALLY want a treatment to work, so it sometimes does... for awhile). This person posted here:
https://www.myparkinsonsteam.com/questions/5b2e...

I started w 2gm a day, adding it to my amino acid supplements I was taking 3 times a day. On vacation I could only manage it twice a day still maintaining my 2gms ,not noticing any symptom change. I credited the B1 at the time but have since went to one dose a day and only taking 1 gm of B1(another busy vacation). I thinked it helped w lowering my dosage ,but now I’m not as sure? I had no side effects from either dose other than what’s mentioned here. Hope that helps.

Thank you. I'll let you know what happens,

It sounds very interresting question! Though i have not heard about this option as one of the therapeutic options for PD!

I take 1000 mg of B1.... 1000 mg of B12...and 500 mg of B6 daily. All in the morning.....I have been doing this for a month....result = No change