Info - pH, Free Acid Value, Layering & Wait Times - Page 3

Thread: Info - pH, Free Acid Value, Layering & Wait Times

  1. #21
    Wow, great info in this thread. Thanks so much, Iamme.

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  3. #22
    Now i get it!!
    Cant thank you enough Iamme.
    Is there a 'peels for dummies' you could direct me to?

  4. #23
    Quote Originally Posted by Iamme View Post
    Layering Products and Wait Times

    Other products are also pH dependent. L-Ascorbic Acid forms of Vitamin C are pH dependent. For good stability and effective action, a good Ascorbic acid product is about 2.0 pH. Since Vitamin C absorbs faster into the skin, you can generally have a shorter wait of about 10 to 15 minutes.
    Thanks Iamme for the great post. I missed it until it became active again today.

    And it got me to thinking, and maybe you/someone can help.

    I wait about 30 minutes after washing my face before applying Retin-A (retinoic acid). The reason that I had always heard for doing so was to reduce the potential for irritation, it was necessary to apply the product to totally dry skin.

    Now I am wondering if there is also a pH reason - since it is an acid, after all.

    Any ideas on this? Sometimes I "cheat" and don't wait the 30 minutes, but will be sure to do so if there is also a pH issue (meaning the application of the drug would be a waste of time and product).

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  6. #24
    Great question! I don't know the answer. But after cleansing, I use a toner to remove all traces of dirt and cleanser. I always add a bit of LA to the toner to bring the pH down. Then I just wait about 10 mintues until the skin is dry.

  7. #25
    grannyD's Avatar
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    As I understand it, the wait time , is for your skin to return to a more "normal" ph as many cleansers are a high ph.

  8. #26
    Quote Originally Posted by grannyD View Post
    As I understand it, the wait time , is for your skin to return to a more "normal" ph as many cleansers are a high ph.
    Thanks GrannyD. I knew that this was the case for L-aa, and it only makes sense that it would apply to other acids as well, like Retinoic Acid. Thanks for clearing that up for me. I've wondered about it for a loooooong time.

  9. #27
    Quote Originally Posted by Randy0875 View Post
    Thanks GrannyD. I knew that this was the case for L-aa, and it only makes sense that it would apply to other acids as well, like Retinoic Acid. Thanks for clearing that up for me. I've wondered about it for a loooooong time.
    Thanks to both of you. I had always assumed you waited for the skin to be completely dry as well. The ph factor makes so much more sense now you say it.

  10. #28
    thank you this was very useful

  11. #29
    Banned DragoN's Avatar
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    A visual of the change in pH and how it affects the acids.


    It's log, not linear. Slight changes of pH around the pKa make significant differences in the FAV. When pH =pKa you have 50% Free acid.

    Hope that makes sense.

  12. #30
    I really appreciate this information Iamme! I am going to study this until I can get a much better grasp of skin ph.

    Another newbie takes her hat off to you!
    TAS

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