Dear Skin Biology,

I recently made a serum for my face with water, alcohol and 5% kojic acid. When I applied my Super CP Serum on top of it, I woke up with an orangey face!

Most of it washed off right away and the rest wore off in a couple of days.

I know it was the copper b/c I did 2 test spots after that on my inner arms. I put some kojic acid on each inner arm. One I covered with Super CP and the other I did not. The kojic covered with Super CP Serum turned orangey.

Do you know what is causing this reaction and is there anything I can do to prevent it?

Thank you in advance,
Kathleen

Dear Kathleen:

The kojic acid is going to bind to the copper and what they do beyond that we aren't sure.

We would not recommend using the two together.

-Dr. Loren Pickart

quote:

going to bind to the copper and what they do beyond that we aren't sure.

Do you know why copper binds with kojic and not say, hydroquinone? I've CPs with HQ without any problems.

Thank you,
Kathleen

Hydroquinone, azelaic acid, mandelic aci, lactic acid, wilddberry suppress tyrosinase. Melanin is made by a reaction where with tyrosinase, an enzyme, and copper. So you lighten in two ways. Kojic acid chelates the copper. It is a fungus, different from the others above. vitamin C does both.

Thanks, David,

So are you saying that kojic will chelate copper in the skin and that is how it lightens? Whereas the others lighten through tyrosinase inhibition?

That would make sense as to why kojic reacted oddly with copper peptides as none of the others you mentioned (and I've used them all!) have had this effect.

Oddly, though, I used to use DY's wildberry serum (which has 2% kojic) with CPs and I never had this problem. It was only when I used a 5% kojic that this happened. Strange!

kathleen