Does the percentage of copper peptide matter?

Why percentage alone is a weak signal

A percentage tells you how much of an ingredient went into the batch. It doesn't tell you what state it's in, whether it stays stable through the product's life, or whether it can reach skin from the base it's sitting in. Two products with an identical number on the label can behave completely differently.

There's also a chain-of-custody question. Raw materials are often supplied as pre-diluted solutions, so a brand quoting a percentage may be quoting the trade material, not the pure peptide. Without knowing which, the number isn't comparable between brands at all.

What actually determines behaviour

• pH — copper peptide complexes are pH-sensitive, and a formula outside the right window is a different ingredient in practice.
• The rest of the formula — chelators, certain actives and some preservatives interact with copper complexes.
• Delivery format — a sealed patch holding essence against skin for fifteen minutes is a different exposure than a lotion that absorbs in ninety seconds.
• Stability over time — what's in the pack on month twelve, not just on day one.

Why study numbers aren't shopping numbers

You'll see concentrations quoted from research and repeated as though they were a target to shop for. They aren't. Study formulations are built for the study — different bases, different exposure, different endpoints — and lifting a number out of that context and onto a shelf label doesn't carry the result with it. We don't benchmark our formula against clinical doses, and we'd be sceptical of anyone who does.

What we disclose and why

We publish our full ingredient list, in INCI order, unabridged, and we'll answer specific questions about what's in the formula if you're checking for a sensitivity or an interaction. We don't publish a headline percentage, because a bare number invites exactly the false comparison this article is about — and because the formulation, not the figure, is the part we spent our time on.