Are supplements safe to take when you buy off of Amazon?

Meagan B Tutor

I have been reading myo inositol is good for PCOS. I also been reading boric something is good for recurring bacterial vaginosis.

Are these safe to take in general or will it cause more harm?

What about health food store? Are those supplements safe to take?

My nurse practitioner acted like she didn't won't to answer my question.