Your dosages are relatively low, so there's nothing to worry about.
If it is helping your neurological problems, continue with it.

There's are a number of studies on high dose thiamine and benfotiamine
stimulating cancer cell proliferation, *admin edit*, but I personally think
it has been blown out of proportion.
*admin edit*


It's analogous to studies on methionine stimulating cancer, but then again
you will find methionine in many foods, so taking say 500 mg of it daily isn't
going to give cancer to you.


Life extension and degenerative disease prevention is basically a trade-off.
The end goal is to improve your quality of life within a reasonable lifespan.

I'm sure you know about the double-edged sword effect of telomerase in
this respect - extending lifespan, but at the potential risk of promoting cancer.