Dry Skin is an inevitable part of aging. “Clinical studies have shown that the level of the skin’s Natural Moisturizing Factor (NMF) drops with age, leading to dry, flaky skin and a compromised barrier,” says Peter Konish, senior director of innovation and product development at skincare provider NeoStrata. And as scientists have learned more about the true nature of the stratum corneum, it has become increasingly clear that proper hydration is essential for maintaining the skin barrier. Just as the body cannot survive without water, the skin cannot function efficiently without adequate hydration.
“Healthy cells exist in an anabolic state, which is the ‘building’ condition of the cell that allows it to maintain physiologic functioning; dehydrated cells, on the other hand, revert to a catabolic state, resulting in cellular hypoxia, cellular damage and toxin buildup,” explains Huntington, New York-based plastic surgeon Elliot B. Duboys, MD. “From an aesthetic standpoint, dehydration compromises cellular functioning resulting in a dull appearance, increased sensitivity and signs of aging.”
More specifically, enzymatic reactions necessitate hydrated skin, says Leslie Baumann, MD, founder of the Skin Type Solutions Franchise System, which independently tests skincare products for efficacy and helps doctors choose products to sell. “Skin hydration is crucial because enzymes that make things happen require water,” she explains. “Water helps the enzymes fold correctly so that they are properly activated. Most cellular processes have particular 3D shape requirements for the molecules, which are influenced by the presence of water. Put simply, water makes the cells work better, whether it is repairing damage, producing important structures or breaking down toxins.”
In addition to aging and environmental concerns, such as sun exposure and harsh cleansers, certain topical skincare ingredients—including alphahydroxy acids (AHAs) and astringents like benzyl peroxide—can lead to irritation and dryness. Common medications, such as statins used to lower serum cholesterol, can also deplete the cholesterol essential for synthesizing the stratum corneum’s lipid membrane. What’s more, popular aesthetic treatments such as peels and laser resurfacing, as well as antiaging topicals, can actually exacerbate skin dryness.
“Any good age management product must contain a retinoid, and since retinoids down-regulate sebum production, they can lead to dry skin, especially in climates with a drying combination of low temperatures and low humidity,” says John Kulesza, president of skincare formulator Young Pharmaceuticals. “That means an effective moisturizer is essential for those using age management products.”
Most skincare professionals would agree that steering patients toward effective moisturizers is necessary. The challenge is choosing among the myriad products now available. Early moisturizers contained a mixture of ingredients classified as occlusives, emollients or humectants. “Occlusive agents, such as squalane, one of my favorite ingredients, and silicone—which is especially useful in preparations for sensitive skin because it is nonreactive—seal in moisture, as do emollient esters such as isopropyl palmitate,” says Kulesza. “Petrolatum (Vaseline), one of the most effective occlusive agents, has been in use for 150 years. It is still the main ingredient in ointments used to protect the skin after treatments like peels and laser resurfacing where the skin barrier is compromised.”
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Rather than seal in moisture from the skin, humectants, such as ammonium lactate, glycerin, sodium PCA and sodium lactate, attract water from the environment and bond with it to hold it in the stratum corneum.
“Humectants, such as medium and low molecular weight hyaluronic acid (HA), can absorb moisture throughout the day and night, and hold a thousand times their weight in water to continually supply moisture to skin cells,” says Dr. Duboys.
Today’s moisturizing products often include a mix of occlusives or emollients to seal in moisture as well as humectants to attract extra hydration. But they don’t stop there. Many also contain ingredients shown to help synthesize skin lipids and other naturally occurring components needed to maintain the health and function of the skin barrier.
Formulators like Tatiana Kononov, director of research and development at Revision Skincare, use the terms hydrophilic (water loving) and lipophilic (oil loving) to talk about skin hydrating ingredients. “Examples of commonly used hydrophilic moisturizers include sodium hyaluronate and glycerin,” she says. “Commonly used lipophilic components include squalane and jojoba esters. Emulsions—mixtures of lipids and water-based ingredients—can be made with different properties depending on skin type, climate and moisture needs of the skin.”
Biomimetic is a term used in skin care to describe ingredients that mimic components found naturally in healthy skin. “State-of-the-art moisturizers are employing biomimetic lipids—fatty acids, ceramides and cholesterol, for instance,” says Kulesza. “They are not really occlusives or humectants. Rather, they support the natural skin barrier, helping it to retain moisture more effectively. The best formulations, in my opinion, contain a combination of humectants, such as HA, occlusives and biomimetic lipids.”
“At NeoStrata we address hydration from multiple pathways with formulations containing traditional humectants that hydrate the surface of the skin and our patented Maltobionic Acid, which provides both hydration and antiaging benefits. We incorporated a natural carbohydrate complex to help strengthen the skin barrier as well as a blend of amino acids that make up the skin’s NMF,” says Konish.
When recommending products to patients, it’s important to look at the quality and combination of ingredients offered. “Every single ingredient in the product counts. They all affect efficacy,” says Dr. Baumann, who wrote the leading textbook on antiaging skincare (Cosmeceuticals and Cosmetic Ingredients, McGraw Hill). “For example, olive oil is an occlusive but it has oleic acid, which has fatty acid legs that curve out. This means the fatty acids cannot pack together as closely as the ones with straight legs (fatty acid chains) such as stearic acid (in shea butter). So using oleic acid can actually make holes in the skin that allow other ingredients to get in better but also let water evaporate off. This means that olive oil is an antioxidant and an occlusive but in the long run leads to skin dehydration.”
Dr. Duboys encourages providers to do their due diligence. “I need to know that the products I recommend have been tested and researched extensively to ensure they don’t over-promise and under-deliver,” he says. “Furthermore, any product must show a minimum of adverse effects, including sensitivity, allergic reaction and overstimulation of the skin.”
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Selecting the Right Products
“When it comes to moisturizers, one size does not fit all,” says Kulesza. “Even youngsters with acne need a moisturizer from time to time, but any formulation for them would need to rely on humectants like HA, while one for a 50-year-old would need to include an occlusive agent like squalane or a heavier emollient such as petrolatum.”
“It is important to have the right levels of hydrophilic and lipophilic moisture for each skin type,” agrees Kononov. “Too much lipophilic moisture can cause issues with skin that is already oily. Additionally, many moisturizers provide short-term hydration to the skin but are lacking when it comes to long-term benefits. Sodium hyaluronate, for example, is an amazing short-term moisturizer, but is most helpful when combined with a moisturizer that has more long-term benefits. Revision Skincare’s Hydrating Serum, for example, has efficacious levels of both sodium hyaluronate and Biosaccharide Gum-1 for short-term and lasting hydration benefits.”
Environmental conditions can also change the skin’s need for hydration. “As a rule, oilier skin does not require as many lipids,” says Dr. Duboys, “but during the harsher winter months or in drier climates the lipid requirement to maintain proper barrier function may increase.”
Patients may also require more intense hydration following skin resurfacing procedures that can leave skin dehydrated. Dr. Duboys has his patients switch to GMC Medical’s Intense Moisture Serum for a minimum of two weeks prior to any resurfacing procedure. “This aids in wound healing and prepares the skin for surgery,” he says. “Additionally, I advise its continued use for a minimum of four weeks postprocedure to ensure proper hydration and healing of the skin.”
How topicals feel and smell to the patient may affect usage as well. Providing samples and offering patients a choice in effective products can go a long way toward ensuring compliance.
“Two newer ingredients in moisturizers worth mentioning are niacinamide, which studies show can improve skin hydration, and acetyl hexapeptide-37 (Diffuporine, Lipotec), which up-regulates aquaporin-3, helping to move water from inside the body to the epidermis,” says Kulesza.
A study published in the April 2016 issue of the Journal of Drugs in Dermatology compared high and low molecular weight HA with a newer crosslinked resilient HA (RHA). Results of the small study indicated that RHA, a proprietary ingredient in ALPHAEON’s TEOXANE line of products, is a more effective moisturizer than the other two types of HA.
The company combines RHA with NovHyal (n-acetyl glucosamine-6-phosphate). “NovHyal is a humectant, but it also helps prevent dehydration by causing the skin to internally make more HA,” says Dr. Baumann.
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“The best and most interesting new technology is SENTÉ with heparan sulfate (HS), a natural component of the skin that actively promotes skin health,” she adds. “HS reminds me of HA. With age, levels of endogenous HS in the skin decrease resulting in visible signs of aging.”
Though long considered effective, HS has not previously been used in skincare formulations because it is unable to permeate the skin barrier. “Endogenous HS is too large and highly polar to penetrate the skin and, therefore, it is not suitable for topical cosmetic products. SENTÉ’s Heparan Sulfate Analog (HSA), on the contrary, provides a size-, shape- and charge-modified, stable HS form that can be safely and effectively delivered to the skin,” says Dr. Baumann. “When used topically, it promotes the formation of a healthy and functional extracellular matrix resulting in firmer, more elastic and stronger skin.” (The role of HS in the treatment of photodamage is explored by Richard L. Gallo, MD, PhD, et al, in the July 2015 issue of the Journal of Drugs in Dermatology.)
Both HA and HS are glycosaminoglycans (GAGs). “These ingredients are well known for being ‘endogenous super-hydrators’ as they bind and hold water, providing not only appropriate skin hydration but also structural integrity as well as preserving collagen and elastin fiber function,” says Dr. Baumann.
As we age, both growth factor and endogenous HS levels fall, which impacts skin quality. “HS or its protein-bound forms (heparan sulfate proteoglycans such as syndecan, glypican and perlecan) modulate key processes in the skin such as cell proliferation, migration, communication and activation. This is due to their capacity to bind, store, present, degrade and amplify key signaling molecules, such as growth factors and cytokines,” says Dr. Baumann. “Thus, mature skin will be strongly activated by its endogenous growth factors as cell signals are amplified by HSA.”
The needs of aging skin can pose challenges for practitioners as patients often need a combination of collagen-stimulating topicals, lightening ingredients and intense hydrators to replace lost NMF. “Fortunately, the skin is the one organ that can be treated directly with topical moisturizers, which are key to maintaining proper skin hydration,” says Kononov.
Linda W. Lewis is the contributing editor of MedEsthetics.
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