By: @drmelissa.co
The concept of the skin barrier has become a part of many skincare aficionado’s vocabulary, but what does it really mean?
It is important to remember firstly that your skin is an organ—the body’s largest—and is the only one that is externally visible. This organ system interfaces directly with your environment, serving as the body’s first line of defence to outside threats including chemicals, allergens, pathogens, environmental factors like UV light, water, and of course, physical injury. Ultimately, the skin is a protective “barrier” between our internal system and the outside world.
The skin also helps regulate body temperature and moisture, and also plays a vital role in the body’s sensory system, allowing us to feel touch, temperature, and pain. The skin is the organ that produces vitamin D when exposed to sunlight (which in turn regulates calcium absorption within the body), and certain cells in the skin layers have immune function. In short, there is much more to this system than its appearance; its role as a barrier is important to maintain so that all other bodily functions can occur with ease. Ultimately, when the skin function is preserved and health overall is maintained, the skin itself looks its best, ages gracefully (not prematurely), and is free of symptoms.
It is important we care for our skin as we would with any other organ. In order for the skin to stay healthy, a symphony of factors must harmonise. Firstly, the skin’s layers must remain functional and intact. There are three layers of the skin organ — the epidermis, dermis, and hypodermis. Each has unique functions, but we will focus on the external layer — the epidermis — for the purposes of this article. This layer and its functions are often what people are referring to when we talk about the skin “barrier”.
The health of the epidermis relies on many things, including its moisture level and pH. These are two things that, when disrupted, can lead to major skin symptoms and conditions — acne, dermatitis, rosacea, general redness and irritation, scarring and pigmentation, and ageing. Think of the epidermis like a brick wall: the main cell type of this layer is called the keratinocyte — keratinocytes are the bricks. These keratinocytes are held together by lipids, like ceramides and other fatty acids — the mortar. They create a waterproof barrier that not only protects us from the outside, but also keeps moisture in. Sebum (any oily substance produced by your skin) combines with the lipids to keep your barrier (or brick wall) strong and intact.
In order for your complexion to thrive, the skin’s components must be working in harmony, creating a healthy pH and a strong brick wall. pH measures acidity and alkalinity. Throughout the body, pH varies; each organ system has its own optimal pH. A healthy skin pH sits between 4.5-6.5 which is considered to be in the acidic range (a pH of 7 is neutral and pH greater than 7 is considered alkaline). The skin pH is maintained by the secretions from oil and sweat glands. When this pH is disrupted, the keratinocytes, lipids and sebum will no longer be in balance. In other words, the brick wall weakens, and skin symptoms arise.
The delicate balance of the skin’s pH is easily disrupted by a variety of factors. Over-cleansing with soaps or foaming cleansers are problematic because they typically are alkaline (have a higher pH) and can remove too much sebum (oil) and dry out the skin. Sebum helps the skin stay moisturised and is slightly acidic in nature. It helps the skin stay within its desired pH. This leads to irritation, and the skin may become dry, itchy, red and/or flakey. It may lead to an overproduction of oil in some individuals. Long-term, a skin environment with an overly alkaline pH and disruption in sebum can make way for bacterial overgrowth and all the issues that come with this — break outs, rosacea, dermatitis, etc.
On the other hand, creating an overly acidic environment on the skin surface is equally as harmful. The use and over-use of exfoliative acids (AHAs, BHAs, retinoic acid) can damage the skin by creating too acidic of a pH, leaving the skin raw and vulnerable. Think of what we know acid to do - it burns through materials. This is what happens when we overuse acids or use acids that are too strong on the skin; the bricks and mortar are stripped back. Some exfoliation of the skin surface can prevent breakouts in particular and diminish signs of ageing by helping to regulate keratinocytes (the bricks in our brick-wall analogy) and prevent the oils (mortar) from getting stuck. However, too much causes an acidic environment on the skin surface and disrupts the protective skin barrier - making way for irritation and the worsening of symptoms.
Overall, the goal is to intervene with the skin less so it can regulate pH on its own. Minor, gentle assistance with the right blend of skincare ingredients can support a healthy skin pH, allowing the brick wall that is our epidermis to flourish and remain strong, resilient to breakouts, irritation, and other concerns like premature ageing.
I cannot stress enough how important it is to be very mindful of what you are putting on your skin. In my practice, I have observed so many skin afflictions that are directly related to over-use or incorrect use of skincare products. These products, while well-meaning, can be incredibly damaging to the epidermis, dysregulating moisture levels, disrupting skin pH, weakening the skin and making it more vulnerable to irritation, breakouts, dryness, dehydration, redness, and more.
Furthermore, there is so much more to healthy skin than the products you apply. Your internal health and inflammation levels, emotional status, and stress levels all shift skin pH and play an enormous role in the ageing process, appearance, and health of the skin. As always, speak with your licensed healthcare provider about the skincare (internal and external) that would suit your skin’s unique needs.
