Thank you for posting your question - We are happy to reply back!

We are checking with Dr. Pickart to see if there might possibly be any interaction if you plan on adding GHK-Cu to this product.

Keep in mind that for a finished product however, Dr. Pickart never suggests to go beyond 3% GHK-Cu as the final concentration. There simply would be no need to and Less is More when dealing with potent cosmeceuticals.

Best Wishes,
-Skin Biology