If a person wants to look into high dose vitamin B1 the Youtube channel EONutrition is a good one.

https://www.youtube.com/watch?v=K4iAPfAFcs0&t=2s  #mce_temp_url#  

It is not usually about satisfying a deficiency of B1. In high doses the B1 acts more like a drug with effects rather than just replacing a normal deficiency.  Some people have responded favorably to high dose B1 that were not deficient in B1.

I have been taking slightly high doses of Thiamine (Benfotiamine) and TTFD B1 and it appears to help my inherited essential tremor. My wife notices and suggests I take my B1 if we run out or go for several days without it. My essential tremors return more of the time. Taking the B1 the only time I will notice it is if I get really tired. Without the B1 supplement I have the tremors sometimes when I am not even tired.