What is the skin barrier function?

I do not intend to write a scientific article about the barrier function, but rather a brief summary so that you know what it is at the user level, and therefore, why it is the first thing you should attend to in order to take care of it.

The skin's barrier function is the skin's natural defense mechanism that protects it against external aggressions (such as bacteria, viruses, pollution and irritating substances) and prevents excessive water loss, maintaining hydration and skin health.

This barrier is composed of:

1. The stratum corneum : The outermost layer of the epidermis, formed by dead cells bound by lipids (such as ceramides, cholesterol and fatty acids).
2. The hydrolipidic mantle : A mixture of sweat and sebum that maintains the skin's pH and its antimicrobial capacity.

🔍 Signs that the skin barrier is weakened

If the skin barrier is damaged, you may notice:
✅ Dryness and flaking → The skin loses water faster than normal.
✅ Increased sensitivity → Itching, burning or redness with products that did not irritate before.
✅ Inflammation or redness → May appear as persistent irritation.
✅ Tightness and roughness → Feeling of discomfort or lack of elasticity.
✅ Increased susceptibility to breakouts or infections → Skin may be more prone to acne, dermatitis, or infections.

🛠 How to repair the skin barrier

✔ Avoid aggressive products : Do not use strong soaps, harsh physical exfoliants or excessive alcohol.
✔ Hydrate with key ingredients : Look for products with ceramides, hyaluronic acid, panthenol, and niacinamide.
✔ Don't overuse exfoliants : Exfoliating acids (AHA, BHA) and retinoids can weaken the skin if used excessively.
✔ Use sun protection : The sun is one of the main causes of damage to the skin barrier.
✔ Repair with occlusive oils : Oils like jojoba or squalane can help seal in hydration.

❓Why is it important to protect the barrier function?

It is essential that the skin barrier is in good condition because it plays a key role in the overall health of the skin and in protecting the body. Here I explain why it is so important :

🔒 1. Protects against external aggressors

The skin barrier acts as a natural shield against:
✔ Bacteria, viruses and fungi → Prevents skin infections.
✔ Pollution and toxins → Reduces inflammation and premature aging.
✔ Allergens and irritants → Prevents adverse reactions such as dermatitis or eczema.

💧 2. Maintains hydration and elasticity

✔ Prevents transepidermal water loss (TEWL) , helping the skin stay hydrated.
✔ Well-hydrated skin looks brighter, softer and more flexible .

⚖ 3. Regulates pH balance and microbiome

✔ Maintains a slightly acidic pH (4.5-5.5) which helps prevent the growth of harmful bacteria.
✔ Promotes a healthy microbiome, with beneficial microorganisms that protect the skin.

🩹 4. Reduces sensitivity and irritation

✔ A strong barrier minimizes problems such as redness, itching and allergic reactions .
✔ If damaged, the skin becomes hypersensitive and reactive to products and environmental factors.

🌞 5. Prevents premature aging

✔ When the barrier is weakened, the skin is more vulnerable to oxidative damage, which causes wrinkles, sagging and spots .
✔ Keeping it strong helps maintain young and healthy skin for longer.

In short, taking care of the skin barrier is key to healthy, hydrated and resilient skin . If you neglect it, the skin can become dry, very sensitive and prone to problems such as acne, dermatitis or accelerated aging.

If you want more technical information, we recommend you take a look at these articles:

Article: "Effectiveness of Non-Irritant Barrier Film in the Prevention of Skin Lesions"

Authors: Researchers from the Carlos III Health Institute
Published in: Nursing Journal , Vol. 12, No. 1, 2009
Link to the full text: https://scielo.isciii.es/scielo.php?pid=S1134-928X2009000100005&script=sci_arttext

Article: "The skin: a comprehensive approach beyond the barrier function"

Authors: Melissa Velilla Contreras and Jaime Avila Cardenas
Published in: Cosmetic, Medical and Surgical Dermatology , Vol. 14, No. 4, 2016
Link to the full text: https://dcmq.com.mx/edici%C3%B3n-octubre-diciembre-2016-volumen-14-n%C3%BAmero-4/512-la-piel-un-enfoque-integral-mas-all%C3%A1-de-la-funci%C3%B3n-de-barrier

Article: "Skin barrier and skin repair products"

Authors: Elsevier Researchers
Published in: Skin. Continuing education in dermatology , Vol. 33, No. 5, 2018
Link to the full text: https://www.elsevier.es/es-revista-piel-formacion-continuada-dermatologia-21-articulo-barrera-cutaneous-productos-reparadores-misma-S021392511830203X