Why Not to Use Retinol and Alpha Hydroxy Acids Together

Skin Care
Why Not to Use Retinol and Alpha Hydroxy Acids Together


Recently, I have received some concerned questions as to whether or not it is okay to use retinoids and alpha hydroxy acids (AHAs) together. For the answer, I turned to the advice of my favorite dermatologist, Dr. Leslie Baumann. On Dr. Baumann’s blog, she states:

Retinol is a highly effective ingredient, but it is unfortunately not a terribly stable one! Alpha hydroxy acids (such as glycolic acid and lactic acid) inactivate retinol, and the two should not be used together.”

As such, even products I love, like M.D. Forte Skin Rejuvenation Eye Cream, Alpha Hydroxy Acid with Vitamins A & E, are less effective than formulations with retinol alone or alpha hydroxy acid alone. Good call, everyone, and thank you for bringing this to my attention! :-)

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12 thoughts on “Why Not to Use Retinol and Alpha Hydroxy Acids Together

  1. bunter says:

    Sorry that this is off-topic, but I’m hoping you can answer my sunscreen question: I know the sunscreen recommendations are 1/4 tsp for face, 1/4 tsp for neck. Does the underside of your chin – the part of your head that connects to your neck, count as face or neck? Are you supposed to coat the front and back of your ears and do they count as face? What about the back of your neck? And does the decolletage count as part of the neck region? Thanks.

  2. Mala says:

    Avene’s triacneal does combine retinaldehyde and glycolic acid. They actually suggest that this combination may be better than retinaldehyde or glycolic acid alone. LRP does something similar in the effacler duo. is it better not to use them?

  3. Nikita says:

    I just read a fairly in depth analysis by the triplehelxian on retinol and why not to layer acidic ingredients with it. Feeling satisfied about following yoru advice thus far! Thanks again for this blog, it’s been immenselvy helpful 😀

  4. Nicki Zevola says:

    Hi @Bunter —

    Wow, that’s precise! Great question!

    The “1/4 tsp for the face” recommendation is based on the calculation from the American Academy of Dermatology that states you should use 2 mg of sunscreen per 1 cm^2 of skin. The average face/neck is 600 cm^2, so you do the math; it roughly ends up being a 1/4 tsp.

    Obviously, when you get into small spaces between the neck and ears and tip of the nose and things like that, this is going to vary greatly from individual to individual. So I would recommend that you stick with a 1/4 tsp and go to 1/3 tsp if you feel you could use more protection. You can also send me your photo and I will tell you if I think you need more sunscreen based on the size of the average face/neck.

    Does that help?

    All the best,

  5. Nicki Zevola says:

    @Mala — Without the data from which they are suggesting this, the assertion that retinaldehyde and glycolic acid together are better than either ingredient alone makes no sense to me.

    Retinaldehyde, first of all, is not as effective toe-to-toe with retinol. Retinaldehyde is vitamin A combined with an aldehyde, not unlike retinyl palmitate, which is retinol combined with a fatty acid. So if you have Formula A with 0.5% retinaldehyde and Formula B with 0.5% retinol, you are going to get much more active ingredient retinol from Formula B, because you’re not getting that extra aldehyde included in the concentration.

    Second of all, retinaldehyde requires a certain pH in order to be activated within the skin, ranging from 5.5-6.5. Mixing it with an acid takes it right out of that range in the skin. Even if retinaldehyde is directly delivered into the skin, where it is at a physiologic pH and can be converted, I don’t see it working as well as a product delivered at a neutral pH to begin with.

    I hope this helps.

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