09/13/2026
Can you use copper peptides with vitamin C? Here’s what 10 skincare brands said about layering GHK-Cu copper peptide serums with Vitamin C L-ascorbic acid.
I contacted 10 skincare brands and asked each one to check with its R&D team about whether its copper peptide serum could be layered with L-ascorbic acid—and, when the combination was not recommended, to explain why.
As a cosmetic chemist, I initially believed that applying the products separately and allowing the first layer to absorb should minimize compatibility concerns. However, allowing a product to absorb does not necessarily establish that two finished formulations are compatible when layering.
As I researched further and spoke with formulators developing GHK-Cu serums, as well as suppliers from whom we source these ingredients, nearly all advised me to avoid layering GHK-Cu and L-ascorbic acid in the same skincare routine.
This does not prove that every GHK-Cu serum is incompatible with every L-ascorbic acid serum when layering. Compatibility may depend on the complete formulations.
My stance is simple: Follow the guidance for the specific copper peptide serum you are using. If the brand advises against layering it with an L-ascorbic acid vitamin C serum, keep them in separate routines—for example, vitamin C in the morning and copper peptides at night.
Next in this series: How do Medik8 Liquid Peptides and Geek & Gorgeous Power Peptides differ from traditional GHK-Cu serums?
Save this copper peptide layering guide.
