pH is important for maintaining skin barrier integrity, knowing what products you should never mix, and everything in between. Let’s break down this idea in the simplest way possible so you can start incorporating it to make smarter decisions about your skincare.

Don’t worry, this won’t be like one of those boring chemistry lessons in school or anything. I’ll keep you entertained.

What is pH?

pH stands for the “power of hydrogen” or “potential of hydrogen,” and is the measurement of how concentrated hydrogen ions are in a solution. In simpler terms, it measures how “acidic” or “basic” a substance is in comparison to distilled water which has a “neutral” pH of 7.0. (1)

Anything below a pH of 7.0 is considered an acid, and anything above a pH of 7.0 is considered an alkaline or “basic.” Generally speaking, acids taste sour and bases taste bitter.

Lemon juice, for example, is sour because it contains approximately 5% citric acid which has a pH of 2.2 meaning it’s highly acidic. On the other hand, baking soda taste bitter because it has a pH of 9.0 (highly alkaline). Two things, by the way, that you should NEVER be putting on your face — more about that later.

To further hammer down this point, let’s give some common examples of basic and acidic substances:

pH 1 = Battery Acid

pH 1.5 – 3.5 = Gastric (Stomach) Acid

pH 2 = Lemon Juice

pH 3 = Soft Drinks

pH 3.4 = Distilled White Vinegar

ph 3.5 = Orange Juice

pH 4.5 = Beer

pH 5.0 = Tea and Coffee

pH 5.5 = Rainwater

pH 6.2 – 7.4 = Saliva

pH 6.8 = Milk

*pH 7 = Distilled Water (the focal point of this scale)

pH 7.4 = Human Blood

pH 9 = Baking Soda

pH 9 = Seawater

pH 9.0-10.0 = Soaps and Detergents

pH 10.5 = Milk of Magnesia

pH 11.5 = Household Ammonia

pH 12.6 = Household Bleach

pH 14 = Lye (Sodium Hydroxide)

Why Does pH Matter For Skincare?

Because the pH of skin influences several factors contributing to its overall health. It’s been demonstrated that skin with pH values below 5.0 are healthier, more hydrated, and have a stronger barrier function than those above 5.0. (2)

Our skin is protected by something called the “acid mantle.” It is a small film on the surface of the stratum corneum composed of fatty acids, lactic acid, pyrrolidine carboxylic acid, amino acids, and a bunch of other sciencey terms and stuff that can be a little overwhelming. Let me translate that to English for normal people.

We have an acid mantle and it kicks BOOTY. Acid mantle = protective barrier on surface of skin composed of sweat, skin oils, and dead skin cells.

This acid mantle is what gives our skin its pH, and ranges anywhere from 4.0 to 7.0, with the average being 4.7. (3) It protects our skin from bacteria, fungi, viruses, environmental pollutants, makes skin soft and supple — it does everything!

Disrupting this lovely skin protector can have adverse effects and lead to stuff like inflammation, atopic dermatitis, dehydrated skin (skin that is both dry and oily at the same time), dry skin, skin sensitivity, acne, malassezia folliculitis etc. (4)

Of equal importance, is the acid mantle’s ability to maintain the integrity of our skin’s moisture barrier and microbiome (i.e. the healthy bacteria that live on our skin).

Just like the bacteria and yeast in our gut that keep us safe from stuff like crohn’s, food sensitivities, autoimmune diseases etc., our skin flora keeps us safe from diseases like acne, rosacea, psoriasis, and dermatitis. (5, 6, 7) Research has shown there is a very close relationship between the pH of skin and having healthy skin bacterium. (8, 9)

What Disrupts Our Skin’s pH and Acid Mantle?

Pollutants, pathogens, excessive occlusion, detergents, soaps, cleansers, heck — even water! (10, 11, 12, 13) I can hear you already, “what WATER?!” Now that you’re utterly terrified, let me calm you down and explain.

Here’s a general rule of thumb: the higher the pH of something, the more disrupting it is to the acid mantle and therefore moisture barrier. So while water isn’t bad per se, “hard water” is. Hard water is simply tap water with a high mineral content causing it to have a pH of 8.5 or more.

Fun-fact: this is why micellar water was invented! Back in the 90s, France was notorious for having “hard water,” so an awesome chemist formulated micellar water so poor french women could clean their faces without nuking their acid mantle.

The biggest acid mantle overkill you need to be worrying about is cleanser. You know that super squeaky feeling you get after using one? Yeah, that isn’t good! It’s an indication that your acid mantle has been disrupted. You should be avoiding that super squeaky feeling at all costs!

The goal is to cleanse your skin without over-stripping it of its natural oils. This is a reason the “oil cleansing method” is so popular. It removes debris and gunk, but leaves your face oils alone. Best of all, oils don’t have pH so you don’t gotta worry about alkalinity when choosing which one to use.

Just like some people’s skin is more sensitive than others, some people’s acid mantles are more sensitive than others. In fact, you might have a sensitive acid mantle even while you don’t think you have specifically sensitive skin.

Making sure you have healthy skin barrier function is one of the most important and beneficial things you can do for your skin.

WHAT IS THE ACID MANTLE?

The acid mantle is your skin’s moisture barrier that keeps moisture in while keeping harmful things out.

It’s composed mostly of fatty acids which create a protective slightly acidic layer on the surface of the skin that prevents bacteria, viruses, and other pathogens from penetrating while also keeping moisture from evaporating.

The problem is that unlike sensitive skin which can show sensitivities right away in the form of redness or dryness, a sensitive skin barrier may not show up immediately.

Oftentimes a sensitive or damaged skin barrier is a long term problem that many people begin to think is just the way their skin is. This can take the form of acne, dullness, slow healing, clogged pores or just an overall congested appearance.

Unfortunately, a lot of the steps people take to improve the appearance of skin can in fact contribute to damaging an already compromised moisture barrier.

The following are 14 factors that can damage your moisture barrier and the solutions that can fix it. If you struggle with problem skin healing moisture barrier could be a simple solution to your skin problems.

WASHING WITH BAR SOAP

Problem: Bar soap is typically highly alkaline, usually a 7 or more on the pH scale.

Besides the alkalinity, bar soap is also a very strong surfactant or detergent so it’s very effective at stripping a lot of the fat from the surface of the skin. The fat or oil is where the acid mantle lives and stripping it significantly compromises the skin barrier.

Solution: Switch to a gentle pH balanced bar soap specifically formulation for skin  which has a slightly acidic pH of 5.5 that perfectly matches the skin’s preferred pH zone.

STRIPPING LIQUID CLEANSERS

Problem: Besides bar soaps, liquid cleansers can also wreak havoc on your acid mantle.

Even if you are using a cleanser specially formulated for problem skin or acne prone skin, it may still be much too alkaline to support healthy barrier function.

This was my exact experience with Vichy Normaderm. Switching to a gentler cleanser solved a lot of my skin problems like the overall congestion and dullness I was dealing with.

CLEANSING TOO OFTEN

Problem: For some people cleansing even twice a day can be too taxing on their acid mantle.

Solution: If you’ve tried other barrier repair fixes and aren’t seeing results, try only using cleanser at night. In the morning just splash water on your face.

PLAIN OLD TAP WATER

Problem: As if skin care wasn’t complicated enough already now water could be standing between you and good skin.

The pH of water is naturally more alkaline than that of skin. Water ranges from 6.5 to 7 whereas skin is happiest between 4.5 and 5.5. For some people applying water too often can disrupt the acid mantle.

Solution: The oil cleansing method is a good option if you’ve exhausted other potential causes of your skin issues.

It’s usually said that the best oil to start with is mineral oil as it’s non-comedogenic and generally not reactive.