Ashley
My experiences are in this thread below. I should clarify that I do not have PD, though when my symptoms started up, they were very much like PD. It took a long time but I did get to see a really good neurologist, but after much of my symptoms had been taken care of. I was diagnosed with dystonia.
There are a lot of studies around the world on PD and B vitamins and those studies led me in the direction of this thread. I have NOT taken Sinemet, either alone or with allithiamine.
http://neurotalk.psychcentral.com/thread218079.html
In the end I have to say that I had a long term B vitamin deficiency caused by candida overgrowth in my small intestine, likely for over a decade. Since I corrected this core problem and started supplementing with B2 and allithiamine my symptoms greatly improved. I tried other B vitamins as well and they made some difference for a bit but that was likely because a shortage of B2 will shut down the methylation process, which is the conversion process your body goes thru to make a range of B vitamins use-able.
BTW a late post on the thread by someone else said that they have to using higher does of allithiamine to great effect for them. I think he/she was diagnosed with PD. You might want to PM them.
I hope this helps.
And BlackFeather, yes, allithiamine is hard to find. I get mine from Life Extension though it is not made by them. The brand I use is Ecological Formulas.