Why The Cream Is Blue

People ask about the colour more than almost anything else, and usually the question underneath it is whether we put a dye in it.

We did not. There is no colourant in the formula. The blue is the active ingredient.

Where the colour comes from

GHK-Cu is a small peptide with a copper ion held inside it. Copper in this state absorbs light in the red and orange part of the spectrum and reflects the blue, which is why copper compounds in solution so often look blue or blue green. Copper sulphate is the example most people have seen in a school lab.

So the shade in the jar is a direct readout of the copper being there and being properly held by the peptide. Nothing else in the formula is contributing to it.

Why this is more useful than it sounds

Think about how much of skincare you have to take on trust. You cannot see retinol. You cannot see niacinamide. A vitamin C serum going orange tells you something has gone wrong, which is useful, but a fresh one looks much like anything else.

Copper peptide is the rare case where the active is visible while it is working.

And it works in both directions. If a copper peptide product shifts from blue toward yellow or green, that is the copper coming off the peptide. The product has not gone off in the way milk goes off. It has stopped being what you bought.

That usually means the pH has drifted, or it has spent too long somewhere hot or bright. It is the one visible expiry signal in the category.

What the shade does and does not tell you

A deeper blue generally means more copper present. But do not read too much into intensity, because the base matters. A thick white cream will look paler than a clear serum at the same concentration, simply because everything else in it is reflecting light too.

What is meaningful is the absence of blue. A copper peptide product that is completely colourless is worth a question, unless it contains an opacifier or a pigment that would mask it.

And a copper peptide product that has gone yellow green is finished. Do not use it.

Two practical things

Keep the jar closed and out of direct sunlight, and do not leave it on a windowsill or in a hot car. Light and heat are what drive the shift.

And it will not stain your skin, your towels or your pillowcase. That worry comes from loose copper, which does stain. Copper held by a peptide in a properly made formula stays in the formula and absorbs cleanly.

If a copper product ever does stain something, that is the same signal as the colour change. The copper is not where it should be.