fwiw, one of 2 active ingredients in generic sinemet is a naturally occurring amino acid l-dopa, it might be synthetically produced but it has been the gold standard for 50years. i''d at least give it a try if you haven't to see what kind of relief you get. if your're worried about long term affects for which there is no substantial evidence imho, i could be wrong, then do some research and estimate how soon there will be a "cure", if you think there might be some disease halting, reversing treatment in the next 5 years then i'd get the best treatment i could get and maximize my quality of life.

the mantra now a days is exercise is the best treatment for pd, it might slow down progression. so if you believe that then one needs to take whatever works best to maximize exercise and for me that means drugs, not supplements.

keep in mind that the cells tightly regulate the production of dopamine, that's why we can eat a 24oz steak without producing huge amounts of dopamine or develop pd symptoms when we fast and don't eat amino acids. so unless you are starving, the extra tyrosine, which is a precursor to dopamine, isn't going to get converted into a lot more dopamine even in a non-pd'er.

keep in mind that before SINEMET was made available years ago, researchers tried everything under the sun, both natural and synthetic, to treat pd. if any of those treatments were very effective we'd be using them now, pd'ers try everything to try to halt progression and treat pd. i've tried a lot of alt-treatments - chleation, iv glutathione, low dose naltrexone, many of the supplements mentioned on the internet, saunas, and nothing really helped. only exercise made me feel better. just my opinion, i'm not an expert.