What is the cutaneous lipid barrier?

The cutaneous lipid barrier is a key element in the health and protection of our skin. This natural barrier, made up of lipids, plays an essential role in maintaining hydration and protecting against external aggressors. Understanding how it works and knowing how to preserve it is crucial to maintaining healthy skin, whether dry, oily or combination.

The cutaneous lipid barrier: what is it?

The skin's lipid barrier is located in the stratum corneum, the outermost layer of the epidermis. It's made up of lipids, mainly fatty acids, cholesterol and ceramides, which form a kind of "cement" between skin cells. This barrier is covered by the hydrolipidic film, a thin layer on the skin's surface composed of an oily phase (sebum produced by the sebaceous glands) and an aqueous phase (sweat).

What is the role of the lipid barrier?

The lipid barrier has several essential functions for skin health:

1. Protection against external aggressors: It acts as a physical and chemical barrier against external aggressors such as pollution, UV rays, climate change and chemical irritants. It also prevents the penetration of potentially pathogenic micro-organisms, helping to maintain healthy skin.

2. Maintaining hydration: the lipid barrier limits transepidermal water loss (TEWL), i.e. the loss of water through the epidermis to the outside environment. By retaining water inside the skin, it helps maintain hydration and suppleness.

3. Regulating skin pH: The hydrolipidic film helps maintain an acid pH at the skin's surface, between 4.5 and 5.5. This slightly acidic pH protects the skin against the proliferation of harmful micro-organisms.

Why is the lipid barrier important?

When the lipid barrier is intact, skin is well hydrated, supple and less prone to irritation. On the other hand, if this barrier is compromised, the skin becomes vulnerable to external aggressions, which can lead to a variety of skin problems:

• Dry skin: A damaged lipid barrier can cause excessive water loss, leading to dry, rough, flaky skin.
• Oily skin: Sometimes, skin that appears oily is actually dehydrated; the skin then produces more sebum to compensate for the loss of water.
• Irritation and sensitivity: a weakened barrier allows irritants and allergens to pass through more easily, leading to redness, itching and inflammation.

How to care for the lipid barrier?

An appropriate beauty routine is essential to protect and restore the lipid barrier. Here are a few tips on how to care for it:

1. Use a gentle cleanser (morning and evening): Choose a gentle, sulfate-free cleanser that doesn't disrupt the skin's natural hydrolipidic film. An overly aggressive cleanser can remove protective lipids, altering the skin barrier.

2. Moisturize: Apply a moisturizing cream suited to your skin type. For dry skin, opt for creams rich in fatty acids, ceramides and cholesterol, which strengthen the lipid barrier. For oily skin, opt for a light cream that moisturizes without clogging pores.Hyaluronic acid, a powerful moisturizing agent, can also be used to retain water in the skin.

3. Maintain pH balance: Use skincare products that respect the skin's acidic pH to avoid disrupting the cutaneous barrier. Products with a neutral or slightly acidic pH are ideal for preserving the hydrolipidic film.

4. Adapt your beauty routine to your skin type: Dry skin will benefit from richer, more nourishing skincare products to compensate for the lack of lipids. Oily skins should opt for non-comedogenic products that don't weigh the skin down, but help maintain lipid balance.

5. Avoid aggression: Limit exposure to factors that can damage the skin barrier, such as hot water, intense cold, and products containing alcohol or irritating ingredients.

What ingredients should you use to strengthen your skin barrier?

Reinforcing the skin's barrier is essential to keeping skin healthy, hydrated and protected from external aggressors. Certain ingredients, when incorporated into your skincare routine, can help restore and strengthen this natural barrier. Here are the main ingredients you should use to support the skin barrier:

1. Ceramides

Ceramides are lipids naturally present in the skin which play a key role in the structure and function of the cutaneous barrier. They act as a "cement" between skin cells, helping to retain water and protect against external aggressors. Using products containing ceramides can help replenish the skin's natural levels, improving hydration and resistance.

• Product example: Moisturizing creams or serums enriched with ceramides.

2. Essential fatty acids

Essential fatty acids such as linoleic acid (omega-6) and alpha-linolenic acid (omega-3) are vital for maintaining the suppleness and integrity of the skin barrier. They help reduce transepidermal water loss and improve barrier function. Vegetable oils such as argan, borage, jojoba and hemp are rich in essential fatty acids.

• Product example: Pure vegetable oils or moisturizing creams containing oils rich in essential fatty acids.

3. Cholesterol

Cholesterol is another major lipid component of the skin barrier. It helps maintain cohesion between skin cells and prevent moisture loss. Skin care products containing cholesterol can help restore barrier function, particularly for dry or damaged skin.

• Product example: Repairing and emollient creams with cholesterol.

4. Hyaluronic acid

Hyaluronic acid is a powerful moisturizer that can retain up to 1000 times its weight in water. It helps to deeply moisturize the skin and improve its elasticity. Used in serums and moisturizing creams, it helps reinforce the cutaneous barrier by maintaining optimal hydration levels.

• Product example: Hyaluronic acid-based serums or moisturizing creams.

5. Niacinamide (Vitamin B3)

Niacinamide is a multifunctional ingredient that helps strengthen the skin barrier by stimulating the production of ceramides and fatty acids. It also has anti-inflammatory properties that can reduce redness and irritation, while improving skin hydration and texture.

• Product example: Serums and creams containing niacinamide (generally between 2% and 5%).

6. Panthenol (Provitamin B5)

Panthenol is known for its moisturizing and soothing properties. It helps strengthen the skin barrier by attracting and retaining moisture in the skin, while helping to repair and protect against irritation.

• Product example: Repair balms, moisturizers and masks containing panthenol.

7. Allantoin

Allantoin is a soothing ingredient that promotes skin regeneration, reducing irritation and redness. It also helps improve the skin's barrier function, keeping it soft and moisturized.

• Product example: Creams and lotions for sensitive skin containing allantoin.

8. Glycerine

Glycerine is an effective humectant that draws water into the skin, helping to maintain optimal hydration levels. It also helps strengthen the skin barrier by reducing transepidermal water loss.

• Product example: Moisturizers, body lotions and gentle cleansers containing glycerine.

9. Soothing plant extracts

Plant extracts such asaloe vera, chamomile and green tea have anti-inflammatory and soothing properties that can calm irritation and support the skin's barrier function. These ingredients are particularly beneficial for sensitive or reactive skin.

• Product example: Soothing serums, moisturizing creams and masks containing plant extracts.

10. Colloidal oat milk

Colloidal oatmeal is renowned for its moisturizing, soothing and anti-inflammatory properties. It helps protect the skin barrier against irritation and external aggression, while restoring the skin's moisture balance.

• Product example: Moisturizers, gentle cleansers and masks with colloidal oatmeal.

Conclusion

The skin's lipid barrier is essential for protecting the skin against external aggressors, maintaining its hydration and preserving its balance. To maintain healthy skin, it's important to adopt a gentle skincare routine adapted to your skin type, using gentle cleansers and appropriate moisturizers, and avoiding irritants that can weaken this protective barrier. Taking care of the lipid barrier helps keep skin soft, supple and resistant to everyday aggressions.