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The skin's pH is delicate. It’s easy to neutralize the acid mantle and alter the pH of your skin by using products that are too alkaline.
We love talking about the skin barrier, and this week we’re diving deeper. We’re taking a closer look at the acid mantle, the outermost layer of the skin barrier. Here’s an introduction to the acid mantle, how it affects the pH of your skin, and why it matters.
If you’re a faithful reader of The Lab, you’re well versed on the finer points of the skin barrier, AKA the stratum corneum. (If you’re new here, there’s still time to catch up. Read some recent coverage on the skin barrier here.)
If you imagine the skin barrier as a brick wall with bricks made of corneocytes and mortar made of lipids, consider the acid mantle as a fresh coat of paint. The acid mantle is a thin film made of natural oils, sebum, and sweat that sits on top of the skin. If you feel a sudden urge to wash your face, don’t act so fast. The acid mantle does important work: it prevents infections, seals in moisture, and helps skin maintain its pH.
Before we go deeper, let’s take a step back and talk about pH. As you learned in chemistry class, pH stands for “potential of Hydrogen.” PH measures the acidity and alkalinity of a solution. A pH of 7 is neutral, like water. A pH higher than 7 means a solution is alkaline. A pH lower than 7 means the solution is acidic.

Our skin is slightly acidic, with a pH in the range of 4 – 6. But its pH is delicate. It’s easy to neutralize the acid mantle and alter the pH of your skin by using skincare products that are too alkaline.
Why should we worry about damaging the acid mantle? A compromised acid mantle can cause skin barrier problems like inflammation, irritation, and, according to some researchers, acne.
At Eighteen B, our formulations were designed to support the skin barrier. That means all our products have a pH in a safe, slightly acidic range. The pH of our Firm + Replenish Serum, Hydrate + Restore Rich Cream, and Revitalizing Hydrogel Moisturizer all fall within a range of 5 – 7.
As skin barrier protection garners more attention in the skincare world, the pH of products is gaining more attention. In South Korea, it’s common for skincare brands to list the pH of their products on the label. In the United States, this is not yet the norm. If you’d like to know the pH of the products you’re using, buy a pack of litmus tests online and test them yourself. Just think how proud your chemistry teacher would be.
Do you have questions? Comments? Topics you want us to cover? We’d love to hear from you. Email us at thelab@eighteenb.com.