What Is Acid Layering And What Does It Do For Your Skin?

The idea of using "acids" on your face might sound a little scary, but skincare acids have been a staple in the beauty industry for some time. Once you understand how they work, it's easy to see why they're so popular.

As per Healthline, the term "acid" probably makes you think of bubbling test tubes and concerns around chemical burns. However, when used in correct, safe concentrations, acids can be exceedingly beneficial for skin, and can be used to manage a range of skin conditions, from acne to age spots.

As per Stylist, Dr. Bibi Maryam Ghalaie explained that, "Topical acids have become hero ingredients in medical grade skincare because of their proven ability to resurface the skin." She also explained that skincare acids can work as "chemical exfoliators," and can not only help with acne and skin tone, but can get rid of dead skin cells. 

Style Story described acid layering as "double cleansing" and recommended that it's best to start with an oil-soluble BHA acid first, followed by an AHA acid.

How should acid layering be used and what are the benefits for your skin?

As per Healthline, there are various acids available to choose from, including salicylic acid (which is best known for fighting acne), glycolic acid (which is often used in anti-aging products), mandelic acid (which is used for smoothing skin), and kojic (which can be used as a brightening agent and is used in many Asian skincare products). There are also a range of lesser well-known acids that can also be used successfully in skincare.

Stylist noted that while acids can be effective, it's important to understand what works best for your skin, especially as there are so many different acids that you can use. Dr. Bibi Maryam Ghalaie explained that, "The two most common types found in skincare products are alpha-hydroxy acids (AHAs) and beta-hydroxy acids (BHAs) which both work as exfoliants but in different ways." As per Style Story, BHAs tend to be formulated at a pH of 3.5 and AHAs are at a pH of under 4.

When using acids in skincare, Healthline noted that it is important to be aware that some acids may interact with each other, which is why it's best not to mix face acids unless you know how to do so properly. For instance, if you mix salicylic acid with any other acid, it will lead to extreme skin irritation, or if you use glycolic or lactic acid with ascorbic acid — like vitamin C — it will halt the benefit of the other acids.

What is acid layering and how does it work?

As per The Klog, acid layering is using a combination of different acids at one time, but experts recommended caution when attempting to layer acids as a form of skincare. Dr. Michele Farber explained that while, "One person may do well with certain combinations while another may become dry and irritated," and explained that this is particularly true when using higher concentrations of acids.

Style Story noted that while combining certain acids doesn't work for some skin types — such as skin that is prone to drying, sensitivity, or redness — for oily skin, combining different acid types can work well.

When it comes to layering acids, it all comes down to the pH levels. It's best to start with a product that has a low pH level and the finish with a product that has a higher pH level. If you use a high pH level first, the second, lower pH serum will purely work to reduce the pH number added to your skin, and thus will lose effectiveness.