Are there skincare products that shouldn’t be mixed together?

Hi, I would like to know what ingredients shouldn't be mixed in a skincare regimen. Ingredients such as Vitamin C with AHAs, acne treatments, and retinol.

It’s crazy …….but there really isn’t a lot of science looking at the layering of skin care products.   Odd, considering that most women/men do this all the time.   So it’s very difficult to say much with any certainty.   But here are some of things we do know:

  1. Chemical sunscreens need to bind with skin cells to be effective so it’s better if they go on freshly washed skin.   Mineral suncreens with zinc and/or titanium can go on top of everything else;
  2. Retinoids like Retin A, retinol, tretinoin, Renova, etc.  should always be used at night since sunlight inactivates them;
  3. Prescription acne and rosacea medications are generallly more effective put on freshly washed skin;
  4. Generally it’s best to put on serums first, followed by lotions and then heavier creams on top; 
  5. With AHAs, is usually better NOT to  put products over them, since part of their effectiveness is their acidity and neutralizing that may make them less effective.

It would be nice to have more data on this.  More on skin care products.

Hope this helps,  Dr. I

Dr. Brandith Irwin, MD

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