Every part of your body has a job, including the skin. The skin is your body's largest organ and the first line of defense against the environment. It's made up of three main layers—the epidermis, the dermis, and the hypodermis—and each has several sublayers.

The outermost part of the epidermis is the skin barrier. According to research published in Current Problems in Dermatology, the primary skin barrier function is two-fold, working to lock in hydration and shield against harsh elements.

While the skin barrier protects you, in turn, you have to protect it. When skin is damaged, environmental stressors are more likely to penetrate the barrier, affecting the body externally and internally. Externally, the skin may appear dry, itchy, cracked, or red as the skin suffers from transepidermal water loss. Internally, a compromised skin barrier can weaken your immunity and increase your chance of getting sick.

Understanding the skin barrier function and why it's important to your overall health will give you a new appreciation of skin and sun care.

What Is the Skin Barrier?

The skin barrier, also known as the stratum corneum, is the part of your skin that you can see and touch, and it's what interacts with the world around you.

The structure of the skin barrier is best explained with the famous brick and mortar analogy. In this analogy, skin cells are the bricks and skin lipids are the mortar. These lipids are made of nutrients like cholesterol, fatty acids, and ceramides, which are collectively referred to as the skin's natural moisturizing factor. Lipids help to moisturize layers deep within the skin and keep skin visibly healthy.

Get to know the skin's layers of the skin barrier

How the Skin Barrier Functions

The skin barrier shields against external threats, like infection, allergens, pollution, chemical substances, and more. As much as its role is to keep unwanted invaders out, it also works to keep water in. This is why the skin barrier is sometimes referred to as the skin's moisture barrier.

Skin barrier function can also determine how healthy your skin looks. If your skin barrier functions properly, your skin often looks plump and supple. If your skin barrier functions poorly, your skin looks dry and dull. A dysfunctional skin barrier also has increased susceptibility to illness and premature signs of aging, like hyperpigmentation and fine lines.

Skin Barrier and Immunity

The condition of your skin barrier is often a sign of overall wellness, and it's important to guard the body against environmental aggressors to prevent disease. This physical barrier contains an intricate network of immune cells that are crucial for maintaining homeostasis and defending against the outside world. Seeing as the skin barrier is semi-permeable, when compromised by an irritant or infectious agent, the immune system kicks in to fight it off and repair the damage.

Protecting the Skin Barrier

Both environmental and lifestyle factors can affect skin barrier health, including exposure to ultraviolet (UV) radiation, pollution, smoking, and stress. Research has shown that the skin barrier can repair itself when harmed, but recovery is slowed with age, so prevention is key.

To maintain skin barrier health and combat skin cancer, be sure to take the proper precautions to protect against radiation and pollution. Wearing a broad-spectrum sunscreen like the EltaMD UV Clear Broad-Spectrum SPF 46 reflects and scatters UVA and UVB rays, which are known to cause free radical damage.

Normal Skin of the skin barrierDamaged skin of the skin barrier

To help restore a damaged skin barrier, the EltaMD Skin Recovery System contains amino acids that support healing, minimize redness, and benefit immunity. The system is powered by AAComplex Technology, formulated to penetrate deep into the skin barrier to strengthen from within.

Caring for your skin barrier will help improve the appearance of your skin and support immunity. Though you may not see it, your skin is working around the clock to keep you healthy and looking great.


  • Lacey Muinos

    Lacey is a Southern California-based freelance writer who combines her passions—fitness, health, and a vegan lifestyle—with her work to help readers feel and be their best. Her work has been featured in Healthline, Livestrong, Verywell Fit, Eat This Not That, KinderBeauty, and more.

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