Understanding dry skin

Your skin is amazing. The average square inch of your skin holds 650 sweat glands, 20 blood vessels and over a thousand nerve endings. Skin performs myriad functions. It has, for example, the ability to regulate your body temperature and it is more than capable of protecting you against the elements. The outer layer of your skin is composed of two elements: a layer of living, viable cells called the epidermis; and the top-most layer, the protective cells known as the stratum corneum. To best understand how skin becomes dry and how to bring your dry skin back to health, we need to understand the stratum corneum.

The stratum corneum is a functional structure, helping your body respond to the environment and maintain your skin barrier's state of health. Healthy skin naturally repairs itself. Unfortunately, skin can become overly dry, and when it does, it struggles to function optimally. Bringing your dry skin back to its healthy state begins with understanding what your skin endures and what it needs.

Healthy Skin

What does it mean to have healthy moisturised skin? We focus on the stratum corneum, the top most layer of skin. Think of the stratum corneum as a brick and mortar wall. The "bricks" are corneocytes (hard, protective skin cells), while the "mortar" are the lipids (a continuous layer that surrounds and protects the corneocytes). Corneocytes are connected by proteins called desmosomes. Inside each corneocyte are Natural Moisturising Factors (or NMFs) which draw moisture into the cell.

The stratum corneum regulates a natural rate of water loss in your skin, a process called Transepidermal Water Loss (or TEWL). Normal, healthy moisturised skin loses about 80 -100 grams of water into the atmosphere each day. The TEWL process is affected by the integrity of the lipid structure and the Natural Moisturising Factor. For healthy moisturised skin, these elements regulate the rate of TEWL and help maintain the proper moisture levels in the stratum corneum.

Environmental moisture loss (dry air, soap, washing)

Your dry skin may be an inherited condition that you live with daily. However, the environment in which you live also impacts the degree of water loss in your skin. The environment is constantly pulling moisture away from your skin surface, and if the air is particularly dry, more moisture gets pulled from your skin.

Everyday activities such as soap and washing further affect your skin's ability to hold onto moisture as well. The water you use to cleanse yourself washes away your skin's NMF, while soap removes lipids from your skin. This combination of activities degrades your skin's barrier and allows even more moisture to escape.

Lower skin resistance & quality

As your skin becomes dryer, there is a breakdown of proper skin mechanisms: without moisture, skin cells become stiff and inflexible, setting the stage for your skin to become cracked and damaged. A loss of barrier lipids further increases exposure of cells to the environment, leading to further water loss and increased skin dryness. Because skin is becoming more vulnerable, its ability to withstand environmental dryness becomes more impaired.

Dry skin

The lack of proper moisture levels in your skin disturbs your skin's desquamation processes. Desquamation is the natural elimination of cells from your stratum corneum - essentially, it is the sloughing off of the dead, top-most layer of skin. When the desquamation process doesn't function properly, dead skin cells collect on your skin and become visible as dry skin flakes.

The dry skin cells accumulating on the surface feel rough and inflexible. They can catch on clothing or other fabric and lead to dry skin itch. With continued dryness, this inflexibility and tightness can lead to physical cracking of your skin which is not only painful, but further exposes skin to drying elements.

As dryness drives deeper into the stratum corneum, physiological functions of skin (such as the natural growth and maturation of healthy corneocytes) become impaired. These underdeveloped, immature corneocytes reach the surface in a weakened state, further reducing skin's ability to withstand dryness and naturally recover from environmental assault.

Moisture infusion & skin protection

If dry skin is to return to a healthy, hydrated state, its moisture levels need to increase. An effective skin lotion provides immediate and long-term hydration. For very dry skin, the best moisturisers contain the right balance of humectants and occlusives in their formulation.

Moisturisers introduce hydration back into skin to immediately soften dry, stiff surface skin cells. Humectants, like glycerin, play an important role in hydration by binding the water within the corneocytes. Humectants not only infuse instant moisture into skin, but also help skin to restore itself.

Occlusives, like petroleum jelly, fill the void of lost lipids in the surface of your skin. They provide a physical barrier to the outside world and seal moisture in the cells to prevent further moisture loss. Additionally, occlusives aid in the dry skin healing process by providing a protective barrier that reduces TEWL and retains the stratum corneum's water content.

Healthy cellular development

Healthy cellular development can occur when your skin is able to lock in moisture over time. A well-balanced moisturiser promotes an environment that over the long-term is beneficial for dry skin healing and repair. With an optimal level of moisture and dryness protection, all of your skin's elements -from lipids, to Natural Moisturising Factor, to desmosomes, to cell maturation - function in unison for healthy moisturised skin.