Not a doctor either.

Japan seems to love creating fat soluble forms of thiamine. I've been experimenting with a form of thiamine called TTFD. TTFD is synthetic, there's a natural form called allithiamine, derived from garlic. There's also another form called benfotiamine. All of these are fat soluble and highly highly available forms of thiamine. TTFD in particular is associated with paradoxical effects where a person can have a temporary worsening of thiamine deficiency symptoms when first consuming TTFD. Thiamine is generally considered very safe, but these supplements are pretty hefty doses, so I would suggest treading lightly.

There's also some thinking amongst some doctors that sub-clinical thiamine deficiencies being more common than most doctors realize [0] [1]

[0] Thiamine Deficiency Disease, Dysautonomia, and High Calorie Malnutrition

[1] https://www.sciencedirect.com/science/chapter/monograph/pii/...