Woman Washing FaceRemember how you had to learn about pH in school? You probably wondered when it would ever come in handy, but you at least memorized the basics. Then promptly forgot them after the test. It turns out that some pH knowledge is pretty important when it comes to health and beauty. You might have heard about pH in terms of diet and the popularity of alkaline food but if you’re not familiar with pH in terms of skin care, it’s time to study up on it because pH-balanced skin care products can make a difference.

(Related: Here’s How To Tell If You Actually Have Sensitive Skin)

To refresh your memory, the pH scale measures how acidic or basic a solution is. Solutions with low pH’s are acidic, while those with high pH’s are basic. (Starting to sound familiar?) On the pH scale, 0 is very acidic, 7 is neutral, while 14 is highly basic.

If you’re wondering how this translates to skin care, Dr. Janet Prystowsky explains that the skin is coated with a slightly acidic film that is secreted from our sebaceous glands (It’s not as gross as it sounds, I promise). This is referred to as the “acidic mantle.” The thought of a film on your skin may not sound too pleasant, but it acts as a barrier to help prevent bacteria or viruses that could cause infection. The normal pH of skin is between 4.5-6.2, hence the “acidic” nomenclature. This is in contrast to the pH of internal blood and tissues, which have a slightly alkaline pH of 7.4. Therefore, the bacteria on the skin on the outside would not be adapted to live well internally, so a barrier is formed.

When you use a skin care product, it can temporarily alter your skin’s pH if you use one with a different pH. Dr. Prystowsky suggests that to keep your skin balanced you avoid any products with extreme pH’s. When you use products that don’t have good pH’s, it can lead to skin issues like rosacea, dermatitis and eczema. She suggests looking for cleansers with a pH between 5.5 and 7 to maintain your skin’s natural pH level.

(Related: Does This Skin Perfecter Live Up to Its Name?)

You may not have realized that your skin care products have pH’s because a lot of them do not have their pH’s written on the bottles. However, many of them have measurable pH’s. You may find some that say “pH balanced.” That’s  a good place to start because they are meant to keep your skin slightly acidic. If you find something that says “non-alkaline” that is also another good option because it means it is more acidic. However, if you already have a cleanser at home that you like but you’re not sure of its pH, you can test it yourself. Dr. Prystowsky explains that a simple litmus test will tell you how basic or acidic your products are. The litmus paper will cost you about $5 and you get to relive your science experiment days while doing it.

Before you start testing the pH of every skin care product that you own, hold up. Dr. Prystowsky says, “Although pH is helpful to keep in mind when purchasing skincare products, don’t overthink it! Very short exposure to products of relatively low or high pH doesn’t cause much damage, however, prolonged exposure can.” This is important in terms of things such as chemical peels. The right peel done, at the right pH, can restore skin. However, if it’s not done properly, excessive peeling or even scarring can occur. Yikes, no thanks.

(Related: I Drank Too Much and Tested Skyn Iceland’s Skin Hangover Emergency Relief Kit—Here’s What Happened)

There are lots of factors to consider when you are choosing skin care products, but keep pH in the back of your mind when you shop for cleansers. If you’ve been using one that throws your skin off balance, but you can’t figure out why, it could be it has an extreme pH. Switching to a non-alkaline one could keep your skin balanced and stop you from needing more products to correct it. And that’s why you will want to remember what pH is next time you head to the drugstore .

(Photo: iStock)