Hydrate and Protect: Skin Restoration

Written by Lacey Elwyn, DO
Edited by Paul M. Graham, DO

Our goal with this article is to provide our readers with the necessary knowledge to read ingredient labels of cleansers and moisturizers and make informed decisions when choosing between the best skincare products!

Winter is coming and so is the struggle with dry cracked skin. Nothing feels better on a cold winter morning than a hot shower. However, after reading this article, you may reconsider your decision to take long hot showers as this often leads to the development of significant skin dryness. The skin becomes dry and cracked in the winter for several reasons: less ambient air moisture, cool and dry outdoor air, and warm and dry indoor air.  Because of these changes, the skin’s natural ability to maintain hydration is compromised. An extra effort in daily skin care is a must in the winter. It is absolutely crucial to choose the right cleanser and moisturize daily. Three properties important to consider when choosing a good and effective moisturizer include: occlusion, humectancy, and lipid restoration. In order to choose a suitable moisturizer, a basic understanding of the skin barrier and the three basic properties of a moisturizer is essential. This article aims not only to educate about the skin barrier and the importance of hydration, but also to provide a detailed discussion on the important properties of moisturizers. Use this information to keep your skin as smooth as silk during the harsh winter months.

Key properties of a moisturizer

1. Occlusion

2. Humectancy

3. Lipid restoration

What is the skin barrier?

The skin is comprised of the epidermis, dermis, and subcutaneous (fat) tissue. The epidermis is made up of several layers with the outermost layer, the stratum corneum, acting as the first line of defense from the elements.

The skin’s remarkable barrier properties are attributed to the stratum corneum. This outermost layer protects other vital organs by preventing foreign substances from entering and by allowing required substances, such as water and electrolytes, from escaping. The optimal water content for the stratum corneum is between 10-30%. Moisturizers have the ability to raise this water content with two essential properties, occlusion and humectancy.

Occlusive Moisturizers
Ingredients: Petrolatum, mineral oil, silicone, dimethicone, castor oil, soybean oil

The fastest way to moisturize the skin is to prevent water from escaping. This is accomplished with an occlusive moisturizer such as petrolatum (most effective), mineral oil, silicone, dimethicone, castor oil, or soybean oil. Occlusive moisturizers create a physical barrier, which prevents water from escaping from the skin. The best time to apply an occlusive moisturizer is when the skin is damp, such as immediately following a bath or shower. A common patient concern is the greasiness of some moisturizers, however, by applying a small amount to damp skin this unpleasant feeling can be avoided.

What we recommend:
Occlusive moisturizer: Vaseline petroleum jelly, Aquaphor healing ointment, Aveeno healing ointment

Humectant Moisturizers
Ingredients: Glycerin, propylene glycol, honey, hyaluronic acid

Humectants work by attracting and retaining moisture.  Hyaluronic acid is a natural humectant found in the skin (dermis) that functions to retain moisture and participate in cellular growth. Humectants only hydrate the skin from the environment if the ambient humidity exceeds 70%. Oftentimes, it is not common to be exposed to such high humidity environments. Therefore, when using a moisturizer with humectant properties, it is much more likely that the water will be drawn from the deeper layers of the skin rather than from environmental moisture. Keeping the body well hydrated by drinking plenty of water will assist in the hydration process from humectant moisturizers. To avoid excess water loss from the deeper layers of the skin to the atmosphere, a humectant should always be combined with an occlusive moisturizer. Most moisturizers combine both of these properties, however, it is recommended to review the ingredient labels prior to purchasing.

What we recommend:

Occlusive moisturizer (petrolatum) + Humectant moisturizer (Glycerin): Cetaphil cream & Curel lotion
Occlusive moisturizer  (petrolatum) + Humectant moisturizer (propylene glycol): Vanicream

What is the skin barrier’s structure?

The stratum corneum is organized into two-compartments, known as the “brick and mortar” structure. The “brick” represents the skin cells (corneocytes) and the “mortar” represents the substance that surrounds the skin cells and forms the lipid matrix.
The skin cells of the stratum corneum contain several proteins called filaggrin and natural moisturizing factor (NMF), which are both important in maintaining appropriate hydration of the skin.

For example, some people with eczema have been found to have a decreased level of filaggrin content in their skin. The “mortar”, otherwise known as the extracellular lipid matrix, is organized into a laminated network, which prevents excessive loss of water from the skin. The three main lipids contributing to the extracellular matrix are ceramides, cholesterol, and free fatty acids. Ceramides comprise 50% of the lipid (fat) content within the stratum corneum. This protein is crucial in maintaining the integrity of the skin barrier. Hot water exposure (i.e. those hot relaxing showers on a cold winter morning) acts to extract the lipids and natural moisturizers from the skin and should be avoided. Instead, brief luke-warm showers are recommended.

Lipid Replacing Moisturizers
Ingredients: Ceramides

Many moisturizers contain occlusives and humectants, but not all contain ceramides. In dry skin, there is a dire need to restore not only an optimal water content but also the lipid (fat) composition with a combination of occlusives, humectants, and ceramides. This can be done with moisturizers that contain ceramides. The synthetic ceramides formulated in moisturizers work to increase the production of natural ceramides in the skin, but this process takes up to 2 months. Thus, in order to achieve the maximize benefit from using a ceramide moisturizer, it must be used daily for more than 2 months.

The BEST moisturizers often contain all three of the above properties: occlusion, humectancy, and lipid replacing.

Lipid replacing moisturizer (ceramides) + Humectant moisturizer (glycerin, hyaluronic acid) + Occlusive moisturizer (petrolatum, dimethicone): CeraVe moisturizing cream

Lipid replacing moisturizer (ceramides) + Humectant moisturizer (glycerin) + Occlusive moisturizer (mineral oil): Eucerin Eczema Relief

Cleansers (Syndets)
Ingredients: sodium cocoyl isethionate, ammonium laureth sulfate

Cleansers also play a role in the optimal hydration of your skin. Cleansers can be soaps, syndets, or combars. Soaps have a basic pH (9–10) and work by solubilizing (breaking down) oil and dirt on the skin’s surface to facilitate easy removal with water. Unfortunately, the natural oils on the skin are also washed away with soaps. Any cleanser that leaves skin feeling tight following bathing is likely a soap or combar with a basic pH and should be avoided. Combars are combinations of true soaps and synthetic detergents. The alkaline pH of these substances work by disrupting the stratum corneum barrier, leaving skin dry and irritated. Examples of combars include: Ivory, Dial, and Irish Spring.

The ideal skin pH is approximately 5.4, therefore, synthetic detergents or syndets were developed to achieve this. These cleansers contain synthetic detergents such as sodium cocoyl isethionate or ammonium laureth sulfate. Syndets are designed to prevent skin alkalization, thus reducing the disruption of the skin barrier. Fortunately, it is possible to cleanse and moisturize the skin at the same time by using select body washes. Body washes should be used with a bath puff to induce both water and air into the cleanser emulsion in sufficient quantity to allow cleansing and moisturization to occur.

What we recommend:
Syndets in bar form: Cetaphil Bar, Dove Bar, Olay Quench Moisturizing Bar

Syndets in body wash form: Aveeno Body Wash, Dove body wash, Oil of Olay daily renewal body wash

THE BIG PICTURE

• The stratum corneum (outermost layer of the skin) makes up the skin’s barrier and prevents loss of water from the skin.
• Optimal water content of the skin can be achieved with a moisturizer with both occlusive and humectant properties.
• Ceramides are a key player in skin barrier function and maintain moisturized skin.

6 simple steps to prevent dry cracked skin in the winter?

1.     Drink plenty of water.

2.     Switch to a syndet body wash with a bath puff, such as Aveeno Body Wash.

3.     Limit showers to 5-10 minutes, with luke-warm water.

4.     Pat dry and immediately moisturize damp skin following baths or showers.

5.     Two months prior to the start of the winter season, begin using a daily moisturizer with occlusive, humectant, and lipid replacing properties (CeraVe Moisturizing Cream).

6.      Buy a humidifier for your home (must clean regularly).

Photo Credit: Fashioncare.com, Gradestack.com, Eliasandwilliams.com, Happyskincare.com, Fryface.com

References:

1. Davis, S. 10 Winter Skin Care Tips. WebMD Feature Reviewed by Louise Chang, MD on December 21, 2007.
2. Blattner CM, Coman G, Blickenstaff NR, Maibach HI. Percutaneous absorption of water in skin: a review. Rev Environ Health. 2014;29(3):175-80.
3. Bolognia, J. Dermatology. Skin Barrier and Transdermal Drug Delivery. Third Edition. p2065-73.
4. Fighting Back Against Dry Skin. WebMD Feature Reviewed by Stephanie S. Gardner, MD on June 11, 2016.
5. Bolognia, J. Dermatology. Cosmetics and Cosmeceuticals. Third Edition. p.2479-91.

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