What time should I wait after AHA exfoliation before serum/moisturizer application?

I know that AHA exfoliants work best at the pH 3-4, and I've read that serums (for example with retinol) could change this pH and therefore change the effectiveness of exfoliation process. What time should I wait after AHA before serum/moisturizer application, and should I wait at all?


  • Unfortunately, there doesn't seem to be any scientific consensus on this issue. Here's an article from the Paula's Choice brand which states that you don't have to wait at all: Waiting Between Product Applications. The PC brand is one I trust because they are more research-focused and science-based than most other brands. There are others, however, that say you should wait at least 20 to 30 minutes, based on anecdotal evidence and theories on how hydroxy acids work. I go for a kind of in-between: After I apply a treatment product, such as an exfoliant or retinol, I wait a few minutes while I floss or brush my teeth.

    I hope the Beauty Brains can shed some more light on this controversial topic.
  • I'm afraid RJ is right, to the best of my knowledge there's no clear scientific consensus on this. I think the Paula Begoun article that she linked to does a good job of explaining the situation. 

    The bottom line is that it doesn't hurt to wait a few minutes between applications but you probably don't really need to. 
  • edited January 2016
    Oh, thanks for the answers. Actually I've read this article but I guess that it is about Paula's Choice products and I am not sure that other brands formulates their AHAs products like she does. Or it is normal for all the cosmeticms products to keep the pH and behave like buffers? 
  • I think her comments could be applied to other products. If an AHA product is formulated at the wrong pH it won't work very well anyway. 
  • Thanks for the answer!
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