Yarai › Conflict library › Copper peptides and vitamin C

Can you use copper peptides with vitamin C or acids?

Not a conflict

Yes. This pair is fine together, and Yarai deliberately does not flag it.

Not a conflict. The claim that these deactivate each other on skin is folklore with weak-to-no supporting evidence.

The claim that copper peptides and vitamin C undo each other circulates widely in skincare communities. We went looking for the evidence behind it and did not find any worth acting on. It appears to be folklore that acquired authority through repetition rather than through anyone testing it.

What Yarai records for this pair

StatusNot a conflict. No rule exists in the engine for this pair.
BasisInternal evidence review; no supporting clinical literature located

Why we don't flag it

We went looking for evidence that this pairing causes a problem and did not find any worth acting on, so there is no rule for it. That absence is recorded deliberately, in the same file as the rules we do carry, so it cannot drift back in as folklore.

Most ingredient apps grow their conflict list forever, because adding a warning feels responsible and removing one feels risky. A rule that turns out to be wrong is worse than no rule: it sends you rearranging a routine that was already fine. Yarai's list is shorter on purpose, and what we removed is written down in the same file as what we kept.

What to do

  1. Use them in the same routine if you want to.
  2. If you would rather separate them out of caution, nothing is lost by doing so, but understand that you are following a preference rather than a finding.
  3. Be more skeptical of copper peptide marketing claims generally than of this particular pairing. The interesting questions about this ingredient are about how well it works at all, not about what it sits next to.

Related questions

So why does everyone say to separate them?

Because it sounds chemically plausible and no one wants to be the person telling you not to worry. Yarai records this as a pair we deliberately do not flag, with the note that no supporting clinical literature was located.

One pair is the easy part

Answering a single question like this one is straightforward. The harder question is the one you actually have: not whether these two work together, but whether the seven things on your shelf work together. Conflicts compound. Two moderate ones in the same evening are not two separate problems, they're one irritated face, and no single-pair answer anywhere on the internet can tell you that.

Yarai scans your products, builds them into an AM and PM routine, and checks every product against every other one, using these same graded rules with the same sources attached. You get the whole picture rather than one pair at a time.

Check your full routine free Get on Google Play

More pairs: Retinol and glycolic acid, Retinol and salicylic acid, Retinol and lactic acid. Or see the full conflict library.