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Protect Your Investment®: AHAs & Chemical Peels

ahas and sunscreen

If you’re interested in consistently bright and smooth skin, then chances are you’re either already into AHAs or you will be once you learn more about them. We’ll explain more about what these acids are, how they work and, most importantly, why AHAs and sunscreen are a very dynamic duo.

Alpha hydroxy acids, aka AHAs, are beloved by many who want to safely exfoliate their skin on a daily basis. If you love Biologique Recherche’s Lotion P50, Sunday Riley’s Good Genes or even the occasional chemical peel, then you love AHAs and you should be wearing sunscreen every day.

Keep reading to discover from NYC-based board-certified dermatologist, Dr. Jeremy Fenton, everything you need to know about AHAs and sunscreen.

What are AHAs and how do they work?

To understand how AHAs work, you first need to understand how your skin works. In the most basic sense, your skin is comprised of many layers and when you’re younger, the top layer of your skin (aka the stratum corneum) routinely sheds to reveal brighter, fresher new skin. But as you get older, that top layer doesn’t shed as much, resulting in longer periods of dull and drab skin. And that’s where AHAs come to the rescue!

“[AHAs] act to disrupt the bonds between corneocytes — the skin cells in the top layers of the skin– which means that they break up the cohesion of the skin cells.”

Dr. Fenton

“AHAs are a class of acids that include glycolic acid, lactic acid and citric acid.  They act to disrupt the bonds between corneocytes — the skin cells in the top layers of the skin — which means that they break up the cohesion of the skin cells,” says Dr. Fenton. “This action breaks the bonds between the skin cells and thus allows the top layers of the skin to slough off and encourages the production of new skin cells.”

AHAs work to exfoliate your skin and allow brighter skin to be revealed. They help even out pigmentation, smooth rough skin and improve the appearance of fine lines and wrinkles. “Once the bonds of the skin cells in the outermost layer are disrupted, the AHAs can penetrate deeper into the skin, which allows it to exert effects on the dermis (the deeper layers of your skin), where it promotes collagen production,” says Dr. Fenton.

Based on the type of acid, the concentration and the pH of the formulation, AHAs can penetrate to different layers of the top of the skin. The deeper the acid goes, the more exfoliation and the more results you’ll see. Think about a chemical peel…those results are usually pretty intense!

What AHAs are most commonly used?

If you’re using a product with AHAs, you’re most likely using glycolic acid or lactic acid. And you probably have a preference based on what kind of skin you have.

“Lactic acid is generally more gentle than glycolic acid. It usually comes in lower concentrations and is useful for sensitive skin that needs a mild exfoliator, or certain skin conditions, like keratosis pilaris,” says Dr. Fenton. “Glycolic acid is a smaller molecule, so it will penetrate deeper and have a stronger effect – sloughing off more skin cells and getting into the dermis to help stimulate collagen. Glycolic acid is also more commonly found in higher concentrations, if desired.” Glycolic acid is the acid most commonly used in chemical peels, just at a much higher level than what you’ll find in a topical product.

There’s also other forms of AHA’s, such as those found in fruits, like citric acid, malic acid and mandelic acid. 

Why should you always wear SPF with AHAs?

“When you’re using AHAs, your ‘natural’ sun protection will be diminished.”

Dr. Fenton

Since AHAs are serious exfoliators, they will thin out the top layer of your skin, making it more susceptible to sun damage. “On top of thinning out the top layer and making your skin more sensitive to the sun, AHAs also remove pigment and decrease the further production of pigment,” says Dr. Fenton. “The stratum corneum and pigment offer very light protection against UV rays from the sun, so when you’re using AHAs, your ‘natural’ sun protection will be diminished.”

What sunscreen should I use?

So on top of knowing that you should be wearing SPF every day no matter what, when you’re using AHAs, the need is extra important. The easiest way to add SPF into your routine is to replace an existing step in your routine with sunscreen.

A great choice is our Mattescreen SPF 40, which doubles as an amazing makeup primer. Quick tip: You may want to gravitate towards a completely mineral sunscreen if your skin is sensitive from AHAs, since mineral sunscreens are generally better for sensitive skin.

Matte Screen is a featherlight formula with a translucent tint that helps you achieve a smooth, poreless look.

+Have more questions about AHAs and sunscreen? Leave them in the comments below!