Skin Barrier Repair: Best Dermatologist Tips on How to Keep Your Skin Hydrated
December 21, 2023
You may already be aware of the importance of skin barrier function—how it can affect the condition of the skin, but how exactly? Skin hydration and the stratum corneum barrier have been active areas of dermatologic research for a good decade. Alongside these developments, consumers are beginning to find their interest piqued about the subject, largely because of the marketing campaigns by industry giants. Before you commit to any product or treatment that promises skin barrier repair, I’ll teach you exactly how to navigate industry jargon so you don’t get confused, worse still, foxed by the deluge of claims—beginning with the basic science of skin.
Skin Anatomy And Physiology
The skin is made up of 3 layers – epidermis, dermis and hypodermis (otherwise known as ‘subcutis’ or ‘panniculus’).
The epidermis has 5 layers – stratum corneum, stratum granulosum (granular cell layer), stratum spinosum (spiny layer) and stratum basale (basal cell layer) from the outermost to the innermost layer.
This outermost layer of the skin consists mainly of keratinocytes, cells which produce a protein called keratin that is a key structural material in the hair, skin and nails. These cells mature over a two-week life cycle. During these two weeks, they are first differentiated from epidermal stem cells in the basal cell layer and are further differentiated as they move upwards towards the epidermis. At the end of the 28-day cycle, they are shed off after reaching the stratum corneum.
The dermis has 2 layers – the papillary dermis and reticular dermis. It mainly consists of fibroblasts, collagen and elastic fibers.
The final layer of the skin called hypodermis is where the adipose tissue (fats) lie.
Concept Of Skin Function And Importance of Skin Barrier Repair
1. Skin barrier function – the skin acts as a physical barrier between the internal and external environments to retain moisture and protect the skin against mechanical, chemical and microbial injury; dysfunction of the skin barrier may result in injury, dehydration, infection and inflammation
2. Immunologic – the skin senses and responds to pathogens; dysfunction of the immunologic barrier may result in infection, allergy, inflammatory skin conditions and in the worst case scenario, could lead to skin cancer
3. Temperature regulation – the skin maintains a constant body temperature by regulating heat loss in the form of sweat production, with insulating properties of fat and hair and with a dense superficial microvasculature; the failure to maintain a constant body temperature could lead to hyper- or hypothermia
4. Protection from radiation – a dark pigment in the epidermis called melanin protects the skin from harmful ultraviolet radiation; disruption of the production of melanin increases the risk of skin cancer
5. Nerve sensation – the skin constantly monitors the environment through sensory receptors and mechanoreceptors found in the skin; dysfunction in the nerve sensation may lead to pruritus, dysesthesia (an abnormal sensation) and insensitivity to injury (as in the case of diabetes and leprosy)
6. Injury repair – the skin has the ability to repair cutaneous wounds in four phases: coagulation, inflammatory, proliferative-migratory (tissue formation) and remodelling; the loss of this ability results in delayed wound healing (e.g. post-radiation treatment)
7. Appearance and quality of life – besides medical conditions, deteriorations to the skin such as skin defects or physiological ageing can lead to psychological distress (e.g. lipoatrophy and vitiligo);
Skin diseases can all be localised to a problem when any one of these functions of skin are disrupted and will be covered in the following chapters.
Skin Barrier Repair And Hydration
You may have heard about the term ‘skin barrier’, which in scientific terms is more accurately referred to as the ‘stratum corneum barrier’. How important is the skin’s barrier function and how exactly does it work?
Skin hydration and the stratum corneum barrier have been active areas of dermatological research for many years. In the last 5 years, commercial companies have started to market their skincare to address this. Before you commit to any product or treatment that promises to skin barrier repair, have a read on to understand what these terms and processes mean.
The Stratum Corneum Skin Barrier
The skin barrier primarily prevents foreign material from entering the human body. But it also does more than just that. It prevents water loss and serves as a shield against the environment. The barrier works to maintain the body’s homeostasis (or stable equilibrium) level, without which the entire body’s organ systems will shut down. The loss of water from the body through evaporation from the surface of the skin is known as Trans-Epidermal Water Loss (TEWL), thus a need to maintain hydration of the superficial cells, known as corneocytes.
Corneocytes are the cells found in the stratum corneum layer, the outermost layer of the epidermis. These cells are formed through cornification, where the skin cells develop tough protective layers or structures, ultimately creating a physical barrier for the skin. When deprived of moisture, dry skin easily develops cracks, fissures and is more susceptible to environmental changes such as the weather.
Ambient humidity also affects the corneocytes. As the level of environmental humidity varies, corneocytes acclimatise by drawing water up from the deeper layer of skin cells, in order to maintain equilibrium with the environment. This explains why our skin feels drier in winter.
Skin Hydration
Skin hydration is a critical factor in attaining healthy skin and a measure of any effective skin barrier repair. A mixture of water-soluble compounds called natural moisturising factor (NMF) have been found to affect water content levels. The arrangement of lipids (fats) in the stratum corneum is also important, as it serves as an effective barrier to the passage of water through the layer. A poor arrangement or deficiency in the corneocyte “cement” can lead to increased transepidermal water loss (TEWL). TEWL occurs as water diffuses and evaporates from the skin surface. While this is a physiological process, excess TEWL is undesirable as it can lead to excessively dry skin.
TEWL and Moisturisers
TEWL has been one of the most commonly used methods in dermatology research to measure skin hydration as it directly correlates with skin barrier dysfunction. Healthy skin would score a low TEWL value as it would mean less water loss.
In the same vein, most moisturisers are put to the test by using TEWL values. A good moisturiser should help decrease TEWL. Moisturisers have remained as a ‘staple’ in basic skincare. Yet, not many may fully understand its function, thus leading to confusion in choosing a suitable moisturiser for their skin needs. An effective moisturiser should protect the skin by stimulating and augmenting its natural barrier function for holistic skin barrier repair, creating the perfect microenvironment for skin healing. Moisturisers will slow down skin ageing as a result.
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What happens if the water content of the stratum corneum falls below a desirable level? Normal desquamation is not able to take place, that is the shedding of the outermost skin layer. With insufficient hydration, skin cells will adhere to one another and accumulate on the surface layer. Visible changes associated with this phenomenon include dryness, roughness, scaling and flaking.
Certain cosmetic ingredients such as ceramide, glycerol (also known as glycerin) and hyaluronic acid have gained prominence in recent years by targeting the stratum corneum water content. How do these work?
Ceramide for Skin Barrier Repair
Ceramides are best understood as the cement joining bricks of a wall together. Genetically, people with sensitive/eczema skin types have deficient ceramide content. Additionally, one’s skin barrier can be damaged by the use of harsh cleansers containing laureth sulfates, over-washing or just due to ageing and hormonal influences such as menopause. The use of ceramides in moisturisers is crucial in preventing and repairing skin barrier dysfunction.
@drteowanlin Ceramide benefits in moisturizer for dry skin Improve skin hydration Reduce water loss from skin Increase skin’s natural ceramides Anti-inflammatory Beneficial for those with eczema, or atopic dermatitis Most ceramides beauty brands refer to are synthetic or animal sources, i.e. bovine in origin—which is also a concern for those preferring a vegan lifestyle. Dermatologist Dr. Teo Wan Lin’s top pick for ceramides is a lesser-known subtype known as phytoceramides. These are botanically derived from plant seed oils and the most prominent phytoceramide of all is shea butter. Derived from the shea tree, shea butter provides a rich source of natural origin plant-based ceramides that can repair the skin barrier effectively. Benefits of phytoceramide skincare Enhance hydration better than synthetic ceramide Improve the recovery rate of damaged stratum corneum Improved immunity Anti-inflammatory #dryskin #moisturiser_for_dryskin #moisturisertreatment #sgskincare #dermatologytiktok #sgtoktok #sgdoctor #dermatologist #tiktoksg🇸🇬 #skincareroutine #skincaretips #skincare101 #skincareproduct ♬ original sound – Dr.TWL Dermatologist
Glycerol for Skin Barrier Repair
This ingredient exists in the stratum corneum as a humectant. It has been demonstrated that changes in the stratum corneum’s water content correlate with the glycerol content in the layer. Such results have driven the development of glycerol-containing moisturisers since decades ago. Check the ingredient list of your moisturiser, this is a fundamental ingredient which should appear in any basic, effective moisturiser used for skin barrier repair.
Hyaluronic Acid for Skin Barrier Repair
Known chemically as sodium hyaluronate, it is a major component of the dermis (deeper layer of the skin). What is less known is that hyaluronic acid is also present in the outermost layer. It plays an important role in regulating the skin barrier function and hydration. Although the skin care industry may recognise hyaluronic acid as a powerful humectant (it attracts water to hydrate the skin), this molecule also participates in cellular functions. Hyaluronic acid influences cell-cell interactions that lead to normal structure of the skin barrier and hence is critical in skin barrier repair.
Conclusion
Though the mechanisms for skin hydration are complex and beyond the scope of this book, a basic understanding about the skin structure and function is crucial to form the basis for choosing appropriate moisturisers for any skin type. Dermatologist-recommended moisturisers target at least one, if not all of these pathways for effective skin hydration to achieve skin barrier repair. With a myriad of drug-store and luxury beauty brands available, it is a useful guide to determine what may be worth your dollar for your basic moisturiser.
Moisturising is a basic step in a skincare routine after cleansing which every one should incorporate. That aside, if you are looking to up your current skincare routine, cosmeceuticals are the buzzword amongst dermatologists. A combination of ‘cosmetics’ and ‘pharmaceuticals’, cosmeceuticals are products with bioactive ingredients that can bring benefits to skin health including skin barrier repair, and are prescribed as adjuncts to anti-ageing treatment.
Tags: ~All Topics, Skin Health, Skincare