Woman touching her shoulder

Understanding skin Skin’s protective barrier

Skin, the body’s largest organ, is our first and best defence against external aggressors. When skin is healthy, its many layers work hard to protect us, but when its condition is compromised, its ability to work as an effective barrier is impaired. Superior skincare choices, and the use of products that help to restore and maintain skin’s optimum pH, help to protect skin and support its natural defenses making it more resilient and less sensitive. They keep skin looking and feeling its natural best and help it to do its job of protecting us.

The role of skin

Skin is the ultimate multi-tasker, performing many functions that are essential to our overall wellbeing.

It plays an important psychological role. As the most visible indication of health, the condition of our skin affects how we feel about ourselves and how others view us. 

But skin’s most important role is as the first line of defence between our bodies and the world we live in. It protects us and helps to keep us healthy by:

  • Maintaining the balance of fluids in the body. Binding in moisture when necessary and preventing moisture loss.
  • Regulating body temperature: it insulates our body, conserves heat in cold conditions and perspires to cool the body down when it gets hot. 
  • Sensing pressure and pain: absorbing shock and alerting us to danger.
  • Guarding the whole body from external aggressors.
Illustration of skin with its different skin layers
Skin plays an important role in protecting our bodies.

What does skin protect us from?

The many external factors that skin protects us from include: 

  • Changes in temperature and humidity: skin helps to regulate body temperature, control moisture loss and maintain the balance of fluids.
  • Disease: skin works to neutralise aggressors such as bacteria, viruses and pollution and prevent them for entering the body. 
  • UV rays: over-exposure to these harmful rays generates free radicals – aggressive molecules that cause cell damage.
  • Pressure, blows and abrasion: skin recognises pain and alerts us to danger. It acts as a barrier and shock absorber.
  • Chemical substances: skin is our first line of defence against the aggressive formulas that we may encounter either in the workplace or at home if we use harsh cleansing products or inappropriate skincare.

Read more in factors that influence skin.

Illustration of skin with skin function
Skin is our first line of defence against external aggressors.

Why does skin need protection?

Skin works hard to protect our bodies, but the external forces it is subjected to can impact on its condition and impair its natural defence. This can affect our overall health as we become prone to injury and infection.

Skin itself can become dry, sensitive and irritable when its protective barrier is compromised. This affects how it looks and feels and can impact on our self-esteem. 

A careful skincare routine, using products that restore and maintain skin’s optimum pH will support skin’s natural defenses, making it more resilient and less sensitive to environmental triggers. The right skincare choices can also prevent premature skin ageing.

Regular care recommended to support skin function
Products that restore and support skin’s optimum pH help to make it more resilient and less sensitive.

What factors influence skin?

Many of the external factors that skin protects us from have, in turn, an impact on skin itself.

UV exposure, changes in climate and temperature and the use of chemicals in the workplace or harsh cleansing products at home can overtax skin’s natural neutralising capability, impair its ability to bind in moisture and weaken its effectiveness as a protective barrier. As a result skin can dry out, become sensitive and prone to the exacerbation of diseases such as Atopic Dermatitis.

Washing too frequently with water that is too hot can also cause skin to dry out, damage its permeability barrier and trigger skin conditions.

An unbalanced diet, little or no exercise, stress, a lack of sleep, smoking, dehydration and certain medicines all influence skin and impact on its ability to operate as a protective barrier.

Skin is also effected by a number of internal factors:
genetics, biological ageing, hormones and specific conditions such as diabetes. Read more in Factors that influence skin.



External factors have impact on skin barrier
Temperature changes and UV rays can cause skin to dry out.
Medicines can influence skin condition
Medicines can influence skin condition.

How does skin work to protect us?

Skin consists of three main layers – the epidermis, the dermis and the subcutis – each of which contributes to skin’s protective abilities.

The outermost layers of skin (the epidermis) form a protective barrier against environmental influences. The external layer of the epidermis - the stratum corneum or horny layer - is made up of dead cells embedded in epidermal lipids and is covered by the hydrolipid film which includes the acid mantle.

Skin barrier with its skin structure
A stable horny layer and intact hydrolipid film work together to limit the penetration of harmful substances and excess water loss.

Epidermal lipids

These are responsible for binding in moisture and creating skin’s permeability barrier, helping to prevent bacteria and viruses from penetrating the skin’s surface.

The hydrolipid film

An emulsion of water and lipids (fats) which covers the surface of the skin and acts as a further barrier against toxins. 

The acid mantle

The water part of the hydrolipid film. It gives skin its mildly acidic pH – the perfect environment for skin-friendly microorganisms (known as skin flora) to thrive and harmful microorganisms to be destroyed. Read more in Skin’s pH.

When skin is repeatedly exposed to certain external stimuli the horny layer thickens to defend the body (for example, when calluses form on hands or feet that are exposed to repeated rubbing). If an irritant or infectious agent passes this first line of defence, skin’s immune system reacts to regenerate and repair the skin. Read more about how skin repairs itself in skin structure and function.

The lower layers of the epidermis are also responsible for the production of Vitamin D, which protects us from rickets.

The other two layers of skin - the dermis and the subcutis - also contribute to skin’s protective barrier. Read more in skin structure and function.

Skin protection in everyday life
Skin thickens to protect areas exposed to repeated rubbing.

How to protect skin’s natural defenses?

Healthy lifestyle choices and a regular skincare routine using appropriate products will help to protect your skin and reinforce and restore its natural defenses. Read more in a daily routine for the face and a skincare routine for the body.

The Eucerin pH5 range has been specially formulated to restores skin’s natural defenses and make it more resilient and less sensitive. All products in the range are clinically and dermatologically proven to be ideal for daily use on dry sensitive and allergy-prone skin and contain our unique pH Balance System with Citrate Buffer which helps to restore skin’s optimum pH.

The formula used in the cleansers combines the pH Balance System with extra mild surfactants
to protect skin’s natural defenses and preserve its resilience. It leaves skin smooth, soft and protected from drying out even with frequent washing. The range includes body cleansers to suit different textural preferences: choose from Eucerin pH5 Washlotion, Eucerin pH5 Soft Shower, Eucerin pH5 Shower Oil and/or Eucerin pH 5 Soap Free Bar. 

The care product formula combines the pH Balance System with Dexpanthenol, known for its regenerative properties. The products restore skin’s natural pH and support long-lasting moisturisation making it more resilient and less sensitive and leaving it looking and feeling soft and smooth. Choose from Eucerin pH5 Soft Body Cream, Eucerin pH5 Cream, Eucerin pH5 Cream F (rich), Eucerin pH Lotion and Eucerin pH5 Lotion F(rich). 

Support skin protection with the right care products
Protect your skin with products that reinforce its natural barrier properties.
The role of skin during or lifetime
Skin changes during our lifetime and has different needs at each stage.

Some areas of the body, for example the hands and face, are more exposed to external forces than other parts. Skincare should reflect the varying needs of skin in different parts of the body.

Skin is a living organ and undergoes significant changes during a person’s lifetime. Each stage has its own demands and skincare choices should reflect these changing needs. Read more in Understanding skin at different ages.

Intelligent sun protection is an essential part of your morning skincare routine. UV rays damage skin, weaken its barrier function, are one of the major causes of premature ageing and can lead to more severe conditions such as cancers. Find out more in the effects of sun exposure and how to protect skin in sun.


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