The SkinSort Blog

Skin Barrier + Acid Mantle

Updated: August 17, 2023

Everyone, and we mean everyone, has a skin barrier.

Skin-experts know a healthy skin barrier results in glowy skin. Not only that, it also protects your body as well!

Your skin barrier is keeping you alive. It sounds dramatic, right? Think about all the bacteria and pollutants that are in this world. Without our skin barrier, we would be fighting infections non-stop.

Taking care of your skin barrier is crucial. Our skin barriers are definitely working overtime. Having a compromised skin barrier can also result in some not-so-great effects.

Keep reading to learn:

  • What is your skin barrier?
  • What does your skin barrier do?
  • All about your acid mantle
  • What does a compromised skin barrier look like?
  • How to take care of your skin barrier
  • Why does pH of skincare matter?

Skin Barrier

Three major layers make up our skin: the hypodermis, dermis, and epidermis.

  1. The hypodermis is the bottom layer that sits right on top of muscle.
  2. The dermis is the middle layer. It houses blood vessels, nerve endings, hair follicles, and glands. Most of our skin collagen can also be found here.
  3. The epidermis is the outermost layer of our skin.

The epidermis has 5 layers. Starting from the deepest layer, these are:
stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum

Your skin barrier refers to this outermost layer of skin: the stratum corneum.

Here, you'll find corneocytes filled with keratin proteins. These corneocytes are held together by hydrophobic lipids in this layer.

Corneocytes are the outermost skin cells. These cells are dead and replaced often with new cells below. In fact, this is why we use acids and retinoids to speed up cell turnover for newer and younger looking skin.

Remember those hydrophobic lipids? The majority of these are cholesterol, ceramides, and fatty acids.

The stratum corneum is 0.01-0.03 mm thick. It does so much work for something so little!

Function of Skin Barrier

Your skin barrier works hard at all hours of the day.

Here are its tasks:

  • regulates water and hydration in your skin
  • prevents water from evaporating
  • fights invasive microbes
  • initiates inflammation when something is off
  • protects your body from impact
  • prevents irritants, allergens, and toxins from entering
  • allows 'good' things to pass through

Phew! That's a lot of work.

A healthy skin barrier will have balanced bacteria, have normal sebum production, is not prone to infection, and a slightly acidic pH.

Why is it slightly acidic? Before we get to how to care for your skin barrier, we need to go into the acid mantle.

Acid Mantle

The term 'acid mantle' was first coined in 1928 by two physicians from Germany. It plays an important part in having a healthy skin barrier. But what is it?

The acid mantle is a very thin and slightly acidic film sitting on top of our skin barrier. It forms from sebum mixing with the fatty acids in sweat.

Before, it was believed the acid mantle only forms from external sources. Recent studies are finding internal factors also play a role in mantle acidification.

As you might have guessed, the pH level of the acid mantle is important.

The right pH level allows our own microbiome to flourish and thus strengthen our acid mantle. A healthy range of pH for our acid mantle is between 4-6.

Our skin has its own bacteria, or microbiome. A healthy microbiome will prevent bad bacteria from taking over the acid mantle.

Having a healthy microbiome is critical to maintaining a healthy acid mantle. A healthy acid mantle creates the perfect environment for our own microbiome to flourish. The two have a symbiotic, or friendly, relationship.

So why is a healthy acid mantle important?
It will maintain the permeability of the barrier, uphold the process of skin cell turnover, and help reduce inflammation.

So what happens when the acid mantle is out of a healthy pH range? This is one way our skin barrier can become compromised.

Compromised Skin Barrier

Signs of a compromised, or damaged, skin barrier can be many symptoms. These include:

  • discolored patches
  • dry and scaly skin
  • itchiness
  • sensitivity
  • inflammation or allergies
  • acne and breakouts
  • microbial infections
  • dullness
  • inability to hold water
  • more sensitive to UV damage

A healthy skin barrier will have a hydrated and healthy appearance.


Your skin barrier can become compromised for a variety of reasons. These include:

  • Too much UV, wind, or cold exposure
  • Pollutants, allergens, or harsh chemicals
  • Over washing or exfoliating
  • Too much humidity or not enough humidity
  • Using products that are too high in pH
  • Using water that is too hot
  • Using too many actives at once
  • Changing products often
  • Certain medications
  • Skin conditions
  • Stress
  • Genetics

Caring for your skin barrier

1) Use the right products for your skin
Keep a close eye on the ingredients in your products. Sneaky harsh ingredients or allergizing ingredients might be hiding in the list. There are tons of resources on the internet that can help you track ingredients (including our ingredient checker!).

2) Be gentle
Be mindful to avoid over-cleansing and over-exfoliating. Using too many actives can be too harsh for your skin as well.

Start slow with active ingredients. This means to start using an ingredient once a week. Once your skin becomes more acclimated, you can increase frequency of use.

2) Use sun protection!
Too much UV can damage your skin and weaken your barrier. Not to mention the premature aging that comes with prolonged sun damage...

If you're outdoors for long periods of time, remember to reapply every 2 hours. Go for sunscreens with higher SPF and PA protection.

4) Watch the pH
The pH of products affects your skin's natural pH. Remember your acid mantle needs a pH between 4-5. Avoid using products that are too high in pH, or too alkaline.

To find the pH of any product, the University of Wisconsin recommends using litmus paper, or pH strips. These strips turn a specific color to let you know the pH level of a product. You can also use a pH meter, which come in many forms, but will cost more than pH strips.

Most products are formulated to be within a healthy pH range (disrupting skin barriers is bad for business!). Testing should be done if you are unsure of a product's pH.

5) Choose nourishing products
Some skincare ingredients are more nourishing and healing than others. Luckily for us, there are many great ingredients out there that help with healing.

The ingredients on this list have studies backing their ability to restore skin barrier health:
Niacinamide, Panthenol, Oat extract, Ceramides, Centella asiatica + derivatives, Vitamin E + derivatives, Squalane / squalene, Sunflower seed oil, Argan oil, Jojoba Oil, Borage oil, Allantoin, Hyaluronic acid, Glycerin, Urea, Linoleic acid (important lipid for maintaining barrier health)

Please note:
Some of these ingredients might exacerbate microbial infections, such as malassezia folliculitis, fungal-acne. Which brings us to the next point.

6) Consult a professional
We cannot stress this enough! A licensed dermatologist will be able to assess your skin's underlying conditions IRL (in real life).

It is best to work with a professional. They will be able to assess any potential causes and find a viable treatment plan.

7) Healthy lifestyle
Research finds a healthy diet and lifestyle play a role in your skin's ability to maintain its barrier. Having a balanced and nutritious diet will affect your skin. In fact, studies show your skin will get benefits from the vitamin C you eat.


Now you know the 'secret' to having healthy, glowy, and plump skin. It all relies on a thin part of our skin called the skin barrier, or stratum corneum.

Your skin barrier keeps both your skin and body healthy. Having a compromised skin barrier will result in negative side-effects. Inflammation, breakouts, and itchiness can take a toll on your day to day life.

Following the steps above, be sure to take care of your barrier.

Further Learning

Now that you know all about the skin barrier, here are some extra reads to boost your skincare knowledge.

Want to become an expert shopper? Read all about our complete guide to understanding an ingredients list.

Want to learn more about how acids help with cell turnoever? AHAs get rid of old cells to keep skin looking younger.

Make the most out of your SkinSort account by creating your routine. This will simplify and organize your skincare products.