Can finasteride be stored for decades?

[Chaul Jhin Kim]

It's tempting to purchase raw pure finasteride powder straight from the source from Chinese manufacturers and cut out the middleman because the amounts needed to take daily are so small, a few grams of the stuff should last a lifetime and it would be hundreds of times cheaper than buying pills. But obviously the cost savings are negated if finasteride goes bad over time.

I guess storing the stuff away from light and heat or maybe even in the freezer might help, along with oxygen and moisture absorbers.

There doesn't seem to be any information about the chemical stability of the finasteride molecule over years and decades.