Why the pH of Your Skin Care Products Matters—& When It Doesn’t

Why the pH of Your Skin Care Products Matters—& When It Doesn’t

If you’ve ever gone down the beauty blog rabbit hole, you’ve probably seen people mention the importance of using low-pH skin care products. You may have even seen diagrams and graphs and long explanations with phrases like “potential for hydrogen” or “molar concentration” that trigger high school chemistry nightmares.

Before you click away and start looking for cat videos on Instagram to avoid the flashbacks, let me reassure you that this won’t be a lengthy science lesson. Instead, I’m going to arm you with just the right amount of easy-to-understand information so that you feel confident when you’re choosing products.

So, let’s talk low ph!

 

Dipping a Toe Into the Science of Low pH

First, let me give you a quick primer on how all of this stuff works.

The pH scale goes from 0-14. Everything below 7 is acidic; everything above 7 is alkaline (or basic—these terms mean the same thing!), and anything with a pH of 7 is considered neutral.

Healthy skin has a pH that falls in the 4 to 6 range, so this is what you want to try to achieve and maintain.

While you might think that a neutral pH is best, the truth is that our skin is naturally acidic. Healthy skin has a pH that falls in the 4 to 6 range, so this is what you want to try to achieve and maintain. Usually, men have slightly more acidic skin than women, but the average pH of healthy skin is typically around 5.

This somewhat acidic environment helps the good, protective bacteria on our skin flourish, and it makes it more difficult for the bacteria that are often responsible for issues like acne, eczema, and fungal rashes to survive.

In order to maintain this healthy environment, your skin has a thin, protective film called the acid mantle. This film is made up of your skin’s natural oils and fats (like ceramides and cholesterol). The acid mantle is your skin’s primary defense against moisture loss, irritation, breakouts, and general signs of aging, so it’s important to do all you can to maintain it.

 

 

How Low Can You Go?

Given this information, nobody could fault you for thinking that it’s best to look for the lowest pH possible, because if slightly acidic is good, then more acidic is better, right?

Nope.

One tricky thing about the pH scale is that it isn’t linear; it’s logarithmic. (You don’t have to dive too deeply into math for this, I promise.)

On a linear scale, a pH of 4 would only be one step more acidic than a pH of 5. On a logarithmic scale, a pH of 4 is actually 10 steps more acidic. If you back up from pH 5 to pH 3, now it’s 100 times more acidic!

This works the same way when you’re moving up the pH scale too (e.g., pH 9 is 10 times more alkaline than pH 8), which is why it’s so important to stay within a narrow range that’s close to your skin’s natural pH.

Basically, you can think of each number on the pH scale like jumping up or down an entire flight of stairs instead of taking them one step at a time. Big difference!

Basically, you can think of each number on the pH scale like jumping up or down an entire flight of stairs instead of taking them one step at a time. Big difference!

 

When Low pH Matters (and When It Doesn’t!)

Before you panic-buy all new skin care, stick with me a little longer.

Not everything in your life needs to be at the “perfect” pH. For beauty purposes, the only times you really need to worry about pH are when you’re buying:

  • Cleansers (including shampoo!)
  • Toners
  • Actives (like retinol, acids, and vitamin C)

It’s also helpful to note that pH only applies to water-based products, so you don’t really need to worry about this for oils, creams, sunscreens, serums, or essences.

 

pH of skin care

 

When you see the term “low pH” in reference to cleansers and toners, it should be referencing a pH somewhere around 5 (5.5 is usually the most popular). Some brands will state the pH of their products clearly (like the Acwell 5.5 Balancing Cleanser), but many will just say “low pH” or “pH-balanced.”

One important caveat for your low-pH shopping: The phrase “pH-balanced” is kind of a nonsense marketing term. It could mean the pH is close to 5.5, or it could mean that the pH is as high as 7, which is far enough outside of the ideal range that I avoid it when possible. Try to look for a specific number, and remember that Google is your friend!

 

Why Some Products Need a Low pH

Personally, I only check the pH of my acids and cleansers. I included toners in the list above because it can be beneficial for some people to have low pH toners on hand, but I don’t stress too much about it for myself.

Cleansers and actives need to be at certain pH levels to do their jobs correctly, though.

 

 

In the case of cleansers, you have to consider that the entire point of the product is to strip all of the oil, dirt, makeup, and gunk off of your skin. If you use a harsh cleanser, this can include all of the protective oils from the acid mantle and even some of the natural moisture your skin desperately needs.

Many foaming cleansers and shampoos use soap-based detergents, which are naturally alkaline. If your face (or scalp!) has ever felt tight and squeaky-clean after washing, it’s probably because you used a high-pH cleanser.

Instead, opt for low-lather milk or cream cleansers with a pH no higher than 6. I personally swear by Bioderma’s Atoderm shower oil. It’s a gentle oil that emulsifies into a low-lather cleanser when you add water, and it does a great job of helping my face and body feel clean but still moisturized.

When it comes to actives, each one performs best at a particular pH level. If your product is formulated too far above that level, it won’t do a great job of exfoliating or unclogging your skin.

 

 

For example, AHAs (like glycolic and lactic acid) should be at a pH of 4 or below. BHAs like salicylic acid should ideally be between pH 3 to 4, but the range is a little more flexible here.

 

Congrats, You Made It!

If you stuck with me through all of that info, then you’re pretty well-equipped to go forth and shop!

For anyone interested in testing their products at home, I like to use these cheap pH strips to check my products. It’s fun, easy and accurate enough for my needs.

Do you have any questions I didn’t answer? If so, drop them in the comments and let’s chat!

 

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