Skin aging is a multifaceted process that is contingent upon a number of factors and causes. Though genetics may be predetermined and shape the pace of aging, extrinsic factors significantly affect and accelerate the process. As skin matures, it is common for dry skin problems to follow, as increased transepidermal water loss (TEWL) can lead to impaired barrier function and dry skin (xerosis). Both skin aging and dry skin are influenced by biological, environmental, and mechanical elements. Like all bodily organs, skin undergoes chronological aging. But, unlike internal organs, skin is in constant contact with the surrounding environment. The epidermis can, at times, be negatively impacted by the environment to create a fragile, weakened, and less functional stratum corneum, thus creating dry skin. Because skin fragility increases linearly and is a biological step, aging and careful selection of skin care products should go hand-in-hand to ensure proper skin health for as long as possible.
THE AGING PROCESS
Human skin protects itself from environmental damage with both sebum, which typifies the skin’s lipid cover, and the barrier layers in the stratum corneum. Sebum consists of triglycerides, fatty acids, waxes, squalene, cholesterol, and cholesterol esters, while the barrier layers contain ceramides, fatty acids, and cholesterol. Many of the fatty acids and triglycerides help to protect skin from environmental damage by keeping the barrier layers balanced and healthy. Unfortunately, as skin ages, the lipid content in the stratum corneum also ages and decreases. The process of aging results in a myriad of physiological changes, including mitochondrial damage, protein oxidation, telomere shortening, compromised vascularity, decreased collagen synthesis, impaired keratinocyte differentiation, and diminished re-epithelialization. These changes can be attributed to the structural integrity of the skin being compromised.
Mechanically speaking, stagnation in the lymphatic system and impaired microcirculation are two of the main culprits of skin aging. Treatments involving manual lymphatic drainage, massage, and connective tissue manipulation can counteract this stagnation by encouraging or mimicking movement and filtration processes in these essential areas.
Free radicals are a tricky bunch. At low to moderate levels they can be beneficial and are involved in various physiological functions and help with homeostasis and cell signaling. However, they can also injure cells around them due to an electron imbalance and, over a period of time, cause great damage. Prolonged damage from free radicals results in oxidative damage to cells and protein and triggers DNA alterations to cause a process commonly known as aging. Antioxidants neutralize free radicals, slowing down oxidative damage, beget tissue homeostasis, and help to control biological damage. This is why antioxidants in skin care actives are important in maintaining the skin’s health and structural integrity as it ages.
Green tea is a rich source of epigallocatechin gallate (EGCG), one of the most powerful antioxidants obtainable. Green tea also contains methylxanthines that stimulate microcirculation. In addition, green tea extract is a potent anti-inflammatory agent and inhibits the action of collagenase. EGCG triggers activator protein 1 (AP-1) which controls cellular processes including differentiation and regulates gene expression. Another interesting and promising discovery is EGCG’s effect on caspace-14. Caspace-14 is an enzyme that works together with filaggrin, a structural protein, to keep the skin’s moisture levels functioning. While an impaired barrier and low sebum levels are causative of chronically dry skin, so is a deficiency of caspace-14. EGCG has been shown to increase caspase-14.
Sebum triglycerides resemble the triglycerides of certain plant oils. The triglycerides of plant oils contain unsaturated acids, like linoleic, oleic, stearic, alpha linolenic, and gamma linolenic acid, and can integrate into the triglyceride balance of the skin. Depending on the oil, plant oils also contain palmitic acid, which is found in the skin barrier, and (unsaturated) essential omega-6- and, possibly, omega-3 acids, the most valuable fatty acid. Linoleic acid, alpha linolenic acid, and gamma linolenic acid produce strong anti-inflammatory actions in the skin. Linoleic acid indirectly reinforces the skin barrier and integrates into the skin’s own synthesis of ceramide 1, a vital lipid for intact barrier function.
Safflower oil is high in linoleic acid and vitamin E. It assists in wound healing and maintaining a healthy barrier and reduces microcomedones.
Evening primrose oil, with its high concentration of gamma linolenic acid, is packed with omega-6 and linolenic acid. Evening primrose oil improves inflammation, reduces transepidermal water loss, and shows remarkable benefits on barrier function.
Hazelnut oil is a drier feeling oil due to its polyphenol and flavonoid concentration, providing fast absorption while maintaining a hydrating, not oily, texture. Hazelnut oil’s high vitamin E content also provides antioxidant benefits to help reverse oxidative damage caused by free radical cells.
Phospholipids are primary constituents of cell membranes. They are naturally occurring lipids, protecting the skin from environmental aggressors and locking in moisture. When used in skin care products, they mimic and improve the skin’s ability to retain moisture, preventing transepidermal water loss, and further protect its barrier. Phospolipids are both hydrophilic and hydrophobic, attracting water and holding onto it. Furthermore, topically applied phospholipids mimic skin structure as they organize themselves into the bio layers of the epidermis.
Amino acids are building blocks of cells and each make different contributions to epidermal structure and barrier function, including tissue strength, wound healing, protein synthesis, and free radical neutralization.
Skin aging is also associated with a loss of moisture. Youthful skin retains its glow, suppleness, turgor, vitality, and pliability due to its hydration level. The main component that influences skin moisture is hyaluronic acid, a glycosaminoglycan and naturally occurring polysaccharide with a unique capacity to attach and retain water molecules. Just as collagen, elastin, and the skin’s fat pads decrease with age, so does hyaluronic acid. Hyaluronic acid is the chief component of the skin’s extracellular matrix molecules. Hyaluronic acid is a humectant that helps keep skin dewy and moist. It is best applied to damp skin and sealed with a cream or balm.
Beta glucan is a film-forming moisturizer, biological response modifier, and remarkable wound healing active. It hydrates as well as or better than hyaluronic acid and locks in natural moisture. Despite its large molecular size, beta glucan is readily absorbed, working through the intercellular lipid matrix. Beta glucan stimulates collagen synthesis, speeds up epithelialization, and soothes and calms skin due to its anti-irritant and strong anti-inflammatory properties.
In cases of extremely dry skin, balms can be especially restorative and offer the best protection from aggressive environmental elements. Beeswax provides many of the known benefits of honey, while creating a restorative barrier to protect and facilitate healing of the skin. It is excellent in the treatment of dermatitis. Beeswax has antimicrobial properties and is effective against both gram-positive and gram-negative bacteria and it is antifungal and a soothing anti-inflammatory.
Hemp seed oil is incredibly nourishing for the skin and provides long lasting moisture and anti-inflammatory benefits. It contains high levels of gamma linolenic acid and is non-comedogenic. The beautiful herb comfrey is found in the best topical rescue balms due to its potent allantoin content and is known to aid in wound repair, accelerate skin healing, and reduce inflammation.
Aloe vera provides an abundance of active constituents including vitamins, minerals, enzymes, sugars, fatty acids, amino acids, and plant steroids. Aloe vera gel contains two hormones: auxin and gibberellins. These two hormones provide wound healing and anti-inflammatory properties. Giberellin acts as a growth hormone stimulating the growth of new cells. Aloe vera’s polysaccharides (long chain sugars) stimulate macrophage production. In skin care products, it also enhances penetration of other active ingredients into the skin.
Oats have been used since the beginning of time for skin ailments. Hydrolyzed oat protein offers anti-inflammatory, skin soothing, and skin softening benefits. It has a photoprotective effect on dermal fibroblast injury and antioxidant activity.
Chamomile is a cheerful herbal plant from the daisy family. It is one of the oldest, most widely used and well documented medicinal plants in the world. Chamomile has been enjoyed and used for centuries in countless cultures for many healing applications. It is a COX-2 inhibitor with anti-inflammatory, antioxidant, and astringent properties.
Nicotinic acid (also generally known as niacin) and niacinamide (also known as nicotinamide) are similarly effectual because they can convert into each other and are often used interchangeably. Both are referred to as vitamin B3. Niacinamide raises the coenzyme NADP intracellular levels involved in hydrogen transfer and cellular respiration. Niacinamide has a soothing and balancing effect on epidermal barrier function, increasing moisture content in the horny layer and reducing transepidermal water loss. Niacinamide accelerates the differentiation of keratinocytes and increases ceramide and protein synthesis.
Panthenol, the provitamin of B5, converts to panthothenic acid within the skin. It is a humectant that is readily absorbed, binding water, enhancing hydration, and preventing transepidermal water loss. Panthenol is very soothing.
Vitamin E (tocopherol) is a free-radical scavenger that protects the skin from reactive oxygen species and oxidative stress and accelerates wound healing.
Sodium ascorbyl phosphate is a hydrophilic and very stable form of vitamin C. It is a powerful antioxidant, excellent in the treatment of photoaging, and protects the skin from UVB-induced lipid peroxidation and erythema. Vitamin C is an essential ingredient for hyperpigmented and sun damaged skin, as it inhibits the action of tyrosinase, thereby decreasing melanin formation. Topical vitamin C increases collagen synthesis, promotes wound healing, and has anti-inflammatory properties, making it useful for acne, rosacea, and aging.
Zinc is frequently used to treat slow healing wounds that can afflict the elderly and diabetics and is critical for wound healing and rebuilding the skin. It reduces TNF-a and IL-6 production and modulation, thereby having a powerful anti-inflammatory effect.
Maintaining proper barrier formation and homeostasis are essential in protecting skin from external aggressors, preventing dry skin and inflammatory skin diseases, and mitigating advanced skin aging. Calcium is essential in regulating skin functions such as skin barrier formation, homeostasis, and keratinocyte differentiation.
Dull skin is common with aging skin. Ginseng is an active in skin care products which encourages radiance and vitality while brightening and toning the complexion. Ginseng raises the coenzyme NADP intracellular levels, benefitting cellular respiration. It improves procollagen type I expression, diminishes matrix metalloproteinase-1 secretion, and increases cell metabolism. Ginseng root contains an abundance of bioactive compounds, including polysaccharides, saponins, B vitamins, pantothenic acid, and minerals. It increases oxygenation and circulation to skin cells, providing a healthy glow. In addition, its anti-inflammatory and antioxidant qualities help protect skin from free radical damage. Ginseng firms and smooths the appearance of fine lines due to its glycoproteins and polysaccharides, which form a biocompatible, weightless film on the surface of the skin.
Skin aging is an unavoidable process due to biological factors beyond control, but it is also heavily influenced by environmental factors that can accelerate aging and easily damage skin with a weakened and insufficient lipid or moisture barrier. Because of these reasons, carefully selecting skin care products to help disrupt aging and dry skin are of importance. Choosing skin care products that are antioxidant rich, assist in wound healing and maintaining a healthy barrier, and provide anti-inflammatory benefits will not only stave off extreme dry skin conditions that are often seen in aging skin, but will also encourage vitality and radiance as skin matures.
As BiON Skincare’s Director of Media Education, Krista McKowen provided education and materials to BiON’s aestheticians and physicians and continues to consult and contribute to BiON’s educational department. McKowen’s ingredient knowledge attracted her to BiON’s science-based products. She has been in the skin care and spa industry for almost four decades. She is currently president of Spa & Esthetic Training & Consulting.