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How to space out Retinoid and Exfoliant (AHA) use optimally?
Say you have a 0.2% retinol formula and want to use it in conjunction with a gentle 10% L-Lactic Acid moisturizer pH 3.5. You’re 35 years old. Both are best used in the evening as both can cause sun sensitivity.
A. Alternate daily used at night.
B. 3 days one week retinol, daily next week exfoliant.
C. Something else?If there’re better forums to ask this I’m all ears!
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6 Replies
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You might get other answers on different forums but none of those responses will be science-based.
That’s because I don’t think a question like this has been scientifically studied. And it certainly hasn’t been studied on your own skin (or whoever you’re talking about).
This is the kind of thing which would best involve a personal experiment.
Try procedure A for one month, then evaluate your skin.
Try procedure B for one month, then evaluate your skin.Through trial and error you could probably find what works best for you.
Of course, you should also realize that just because it works for you doesn’t mean your experience would be generally applicable to everyone else.
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Market research needed to answer.Wrong forum.
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Well, I am more of a daily that changing routine with almost any product (mainly because simplicity leads to more consistent use) so not sure about what answer give you because skin sensitivity is very variable but at least according to Paulas Choice instructions (I particularly think this brand has good formulations, market research and is more honest than the majority of brands nowadays) you could be able to use them both together. It is true that 0.2% is not the lowest concentration but neither the highest. Did you try both at the same time at a lower concentration?
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Hi @Zinc, I agree that the only way to learn it is through trial and error. However, the concentration of retinol is not very high. I would advise checking the pH of your lactic acid moisturizer. pH plays a large part in determining the potency of the AHA. AHAs need pH <4 (I think 3.75) to be active. Most of the commercial products are neutralized and I would not be surprised if your moisturizer is >5. That would actually mean that the acid is effective and is only added for a marketing claim. If my assumption is correct, you can use them together (not sure that acid would do much though). Use sunscreen. Both of the products increase sensitivity to the sun.
I tried a product with 10% lactic acid at a pH of 6. It was drastically different from the same concentration at pH <4. The latter tingled so much that I was not able to leave it on my skin (my skin is not sensitive at all). So if your moisturizer is “gentle”, I am afraid it’s not working.
https://www.truthinaging.com/review/glycolic-acid-and-ph-levels-getting-the-balance-right
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pKa of lactic acid is 3.86. So, pH = 3.86 will have 50% free lactic acid
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Retinols actually make the skin more resilient to sun damage. They boost collagen and thwart photoaging. A trial retinoic acid user may have turned red as a lobster and got a sunburn. The former will happen because it is a side effect. The latter will happen because it’s what happens with the sun. Hence the early concern. The main reason retinol is used at night is that light deactivates it.
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