The vitamin b1 pills didn’t work so they injected vitamin b1 into patients with Parkinson’s in very high doses and saw major improvements.
I think their saying people have trouble digesting b1, so they injected it instead.
Sugar, caffeine and alcohol deplete vitamin b1. Also chocolate.
Maybe modern diets deplete b1?
https://www.researchgate.net/publication/256201463_High-dose_thiamine_as_initial_treatment_for_Parkinson’s_disease
Good stuff. Thanks for sharing.
Well I hope it helps someone out. 
I’ve heard people in AA say that B12 shots help with alcoholic withdrawal.
If you have Parkinson’s disease you could try adding black pepper to your b1 supplements to help absorption. Take b1 in the morning an hour before your caffeine fix. Take it with black pepper.
Turmeric can’t be absorbed without black pepper. Black pepper increased turmeric absorption by something like 500%.
So I’m thinking if you take b1, avoid caffeine for an hour and take it with black pepper.
This is just my opinion though, but it makes sense.
If you have a b1 deficiency, this may help.