Can I use copper peptides with L ascorbic acid?

Why isn't there a simple yes or no?

GHK is a small peptide that binds copper. Its copper complexes change with chemical conditions, including pH and the relative amounts of peptide and copper. That makes the finished formula relevant to the answer. It does not justify a blanket claim that L ascorbic acid always destroys copper peptides.1

L ascorbic acid also has its own formulation problem: it is unstable when exposed to oxygen, and a topical product needs adequate stability and skin penetration to be useful. A vitamin C claim on the bottle cannot do the job of a stable formula, even if the lettering is very confident.23

What about products containing both vitamin C and peptides?

Peptides and pure vitamin C can appear together in a finished skincare formula. For example, Vichy Liftactiv Peptide C Ampoules combined 10% pure vitamin C with rice and lupin peptides, hyaluronic acid and mineralizing water. Rice and lupin peptides are different from a copper binding peptide such as GHK, so that combination is not a reason to treat all peptide serums alike.45

How should I handle two separate serums?

Check the compatibility directions for both products before deciding to layer them. If you want to avoid combining them in one application, using them in separate routines is a practical scheduling choice, not a claim that the ingredients require a particular gap. Choose a routine around the directions for your two products, rather than making the bathroom shelf negotiate a treaty.1

What can I expect from the ingredients?

Correctly formulated topical vitamin C can help reduce fine lines and wrinkles and protect against damage associated with sun exposure. Copper peptides are used for their antioxidant activity and support of collagen and elastin production. Peptide performance also depends on how effectively the peptide reaches and interacts with cells, not simply whether the ingredient appears on a label.2356

Vitamin C creams can cause stinging or redness when first used, and these effects generally settle with continued use. That possibility matters separately from the compatibility question: discomfort after applying vitamin C does not, by itself, identify a reaction between vitamin C and copper peptides.6