Do supplements need to be kosher?

My parents who consider themselves more “religious” than me take multiple supplements and other homeopathic remedies that don’t have a hashgacha and in some cases may very well be treif. They consider my refusal to do so silly yet they buy specifically kosher enzymes just for me while they have hashgacha-less ones for themselves. They insist it isn’t food so it doesn’t need a hasgacha.

EDIT: just to clarify I’m not some homeopathic nut, it’s just my parents. I just take enzymes because I’m lactose intolerant.