| I don't have any info on your question, but I just wanted to say that if you want to supplement thiamine you could try bumping that dosage way down. One hundred mg is 6667% of the currently estimated need for thiamine in the healthy person. I take thiamine myself and buy it in that dosage, but break them into fourths or even smaller if I can. Even a fourth still leaves us with a huge dose.
Oh, I also take mine in the middle of the day because in the morning I take a multi-vitamin tablet which also has thiamine. So I take the pure thiamine tablet portion in the afternoon to space the doses in time.
Also, have you considered that it might be just coincidence rather than cause and effect that you are taking thiamine and are having fatigue? Try going off it for some time. See if the fatigue abates. Later begin the thiamine again and see if the fatigue returns.
Off topic-- Does anyone know if Dave's spelling of thiamin versus my spelling of thiamine is one of those Bristish versus USAmerican differences? Actually, I spell it every time as Dave does, but then my spell checker (American) tells me to add an "e". I looked on my bottle and it is also spelled with an "e" there. But I do pronounce it with a shirt "i" in the final syllable, further suggesting that I must have seen it with no "e" for most of my life.  | 
