Mucuna Pruriens has almost eliminated the very noticeable shaking of my neck/head and hands for 15 years. Doctor said he thought it was "essential tremors", not Parkinson's but I'm not so sure. I suspect he was influenced by my otherwise excellent health. Even if I have ET, MP may help this symptom for those with Parkinson's.
After one brand of MP (Herbs Forever) had no effect after months of use, I persevered and ended up finding two excellent products online. I tried both for comparison and found them to be equally effective: Barlowe's Elixirs and Keter Wellness. With each, improvement was noticeable in less than a week; I followed the dosage on the bottle - two capsules per day. If I don't take the MP for several days, some shaking returns.
I was so embarrassed for so long and now people don't stare at me any more. There is just a little trembling left in one hand and a little flair up under situational stress.