I'm not quite sure how to use this. Do you have to not wear nail polish when using this, or does it work wearing polish and just using around the cuticles? I have thin, dry, brittle nails and won't wear polish during treatment if that will really help my nails, and if it has to be used directly on bare nails.

It would be best to not wear the nail polish.

I think the tin peptides help new nail growth and also reduce the friction of the nail bed that resists nail outgrowth. In some of our studies, we have observed very fast nail growth that seem to greatly exceed normal nail growth.