Please tell me if you know if I can use a phytic acid leave on exfoliator before applying copper peptide products. I ask because I read on a website that phytic acid blocks copper from entering the skin. Thanks.

Phytic acid is inositol hexakisphosphate, inositol polyphosphate.

I don't know if it would react with the copper peptides. It seems to be very safe on skin.

You could try it as an exfoliator, then cautiously follow this with a copper peptide product. But only do this on a small area of your skin.