Our skin barrier is our first and best defense against external aggressors. Being the largest organ, it protects us from the environment and harmful pathogens. Even though this defense from the outside is crucial, the skin barrier serves another extremely important function. It prevents hydration loss from the inside.[1]
Skin Barrier Function
Protective shield
The skin plays a key role as the protector, defender, and gatekeeper of your body. Finer and thinner than plastic wrap, the epidermis produces a protective shield against the entry of noxious materials such as bacteria or allergens from the surrounding environment. All the elements and substances you are exposed to every day such as chemicals, pathogens, and sunlight has the potential to inflict harm. The human skin does a good job of blocking out all these undesirable substances and forces.[2]
Maintain hydration
The primary job of the skin barrier is to keep water-rich internal organs from drying out by preventing water loss in dry environments. Our skin barrier’s number one task is to hold our body water inside.[3] Without this protection, the body would not be able to sustain its normal activities, and everything from major organs down to the tiniest cells would stop functioning.[4]
Structure of the Skin
Our skin is made up of three main layers: the epidermis, the dermis, and the hypodermis. The epidermis consists of five smaller layers, and the uppermost or surface layer is known as the stratum corneum or horny layer.[5] When the term skin barrier is used, experts are usually referring to the stratum corneum. This outermost layer is the barrier preventing loss of water.[6]
Brick wall analogy
The stratum corneum barrier is comparable to a brick wall. This tissue is made up of multiple stacks of flattened cells called corneocytes, each of which is encased in a thick coating of fat called lipids.[7]
Credit: Michał Grosicki at Unsplash.com
Bricks: the corneocytes, which are dried out, non-living skin cells that are ready to shed
Mortar (cement holding the bricks together): the intercellular matrix, which is composed of lipids that surround the corneocytes
- The lipids in the mortar, commonly referred to as the lipid barrier, are responsible for maintaining skin hydration[4]
- Minimizes water loss and is essential for strong, healthy, hydrated skin[8]
- Prevents environmental chemicals and irritants from entering the skin[9]
Damaged Skin Barrier
Dry, itchy, irritated, and sensitive skin are all signs of damage or a weakened skin barrier. When the lipids in the mortar begin to break down and form cracks, the skin loses water, gets dried out, and becomes more permeable to irritants and allergens.[10] Once irritants or allergens penetrate the epidermis, they may trigger inflammation and itching. A damaged skin barrier can also lead to skin conditions such as psoriasis and atopic dermatitis.[11]
Causes of a damaged skin barrier
- Harsh products: include solvents, detergents, perfumes and irritating chemicals[12]
- Excessive cleansing: water and soap can strip the lipids and natural moisturizing factors in the stratum corneum[12]
- Environment: wind and cold weather can dry out the protective skin barrier[13]
- UV rays from sunlight and tanning beds: over-exposure to these harmful rays generates free radicals, aggressive molecules that cause cell damage[14]
Maintaining the Skin Barrier
Skin barrier cream
The purpose of a skin barrier cream is to help the epidermis retain water. A good skin cream acts as a sort of short-term shield that helps support the skin barrier.[15] Because cleansing can dry the skin, it is best to apply moisturizers after bathing.[16] This will help trap water in the surface cells of the skin.
The best kinds of creams contain ingredients that block water from exiting the skin’s surface, such as glycerin and hyaluronic acid.[17,18] These creams help draw water into the skin and keep the skin hydrated.
Reduce exfoliation
Scrubbing your skin too hard and too often can cause unnecessary stress to the skin barrier. For those with sensitive skin, over-exfoliation could be the cause of redness and inflammation.
Use correct product ingredients
- Gentle hydrating cleansers are acceptable for daily face washing. Avoid astringents that contain alcohol or witch hazel. These can dry out the skin and damage the barrier[19]
- Niacinamide boosts ceramide production.[20] Ceramides are important for structuring and maintaining the water permeability barrier function of the skin and improve lipid barrier function for brighter skin[21]
- Linoleic acid and omega-6 fatty acid are essential fatty acids that must be obtained through diet or topical applications. They help with inflammation and repairing barrier function.[22] Sunflower oil, fish, and walnuts are some dietary sources of these fatty acids
- Antioxidants protect the skin against free radical damage and can reduce the signs of aging. These can be found in green tea extract and in foods such as ginger, berries.[23-25]
Wear sunscreen
Use a broad-spectrum sunscreen daily even when it’s cloudy outside or if you’re under shade.[26] Broad-spectrum sunscreens block both ultraviolet type A (UVA) and type B (UVB) rays. Make sure you wear sunscreen while driving because sunlight entering through the side windows are a major source of sun exposure for some people. Sunscreen defends your skin barrier by protecting it from the sun’s damaging UV rays which can cause cell damage and signs of aging.
