Occlusives are one of the three pillars of moisturizers. They work alongside humectants and emollients to keep skin feeling soft, hydrated, and glowing. Occlusive substances work by helping to form a physical barrier or seal on the outer layer of the skin, to prevent trans-epidermal water loss; keep moisture locked in. Although they don't increase the moisture levels of the skin, they can help prevent water reserves from being drained by external sources like wind, a dry environment, or injury.
Occlusives can come from plant sources, like candelilla wax, carnauba wax, palm kernel and heavy oils like macadamia, castor, and cocoa butter. Others, like mineral oil, petrolatum, paraffin come from refining crude oil. Some are nature-identical like allantoin, a compound found in many natural sources, but is often produced in a lab to cost and sustainability reasons.
You are already familiar with products high in occlusive agents without even knowing it. o get an idea of what they feel like think of barrier creams, foot creams, and good old Vaseline, which is made from 100% petrolatum - an ingredient derived from crude oil.
Occlusive ingredients can feel heavy and greasy on the skin - therefore it's best to include them along with lighter-feeling ingredients when creating moisturizing skin care products.
Natural occlusives:
Beeswax is composed of monoesters, diesters, and triesters, as well as hydrocarbons, hydroxypolyesters, and free fatty acids. Because of the nature of beeswax, including the moisturizing and soothing qualities, it is very frequently used in moisturizers.
Vegetable waxes - for those that don't like using animal products, there are some great vegetable waxes that are a great substitute for beeswax. Carnauba wax, also called Brazil wax and palm wax, and Candelilla wax, and Palm kernel oil are great choices,
Plant oils and butters high in Oleic Acid. In general, most plant oils are considered emollients, but some oils, particularly those high in oleic acid, also work also have occlusive properties. These oils often have a thicker, greasier feel and include olive, avocado, rice bran, macadamia, castor, and soybean oil and shea and cocoa butter.
Lecithin is a fat that is essential in the cells of the body. It can be found in many foods, including soybeans, chickpeas, and egg yolks. It is a multi-purpose ingredient that helps pump up the skin's barrier function and also be used as an emulsifier for oil in water emulsions. It can also help with serious dryness and eczema. It can be derived from many plant sources including sunflower and soy.
Cocoa Butter is an amazing occlusive. It has properties of all the moisturizing components and is a go-to for the skin. One of the benefits of cocoa butter is the high tocopherol content. This is a cluster of compounds that together contain a lot of Vitamin E, and is sometimes referred to as a form of that key vitamin. Tocopherol is a friend of the skin due to its antioxidant properties. These protect the skin from UV rays, and ultimately make it look firm and healthy. By boosting collagen, Vitamin E also keeps your face free of nagging little spots and lines and wrinkles that may come from age.4
Allantoin - While allantoin occurs naturally in botanical extracts of the comfrey plant, it is generally chemically synthesized to be nature-identical for sustainability reasons. When formulating, allantoin will come in the form of a white powder that is dissolved in the water phase. Allantoin helps to create a barrier over the skin while healing and promoting cellular regeneration.
Non-Natural/Synthetic/Petroleum-based Occlusive agents
There are many great plant-based or natural occlusives, but some of the occlusives ingredients most popular with dermatologists and professional formulators are derived from petroleum products or made with some synthetic ingredients. Regardless of whether you use choose to use all-natural ingredients or synthetics, it's important to understand the what options are available.
Petrolatum, or petroleum jelly and mineral oil. These are the two most popular occlusive ingredients because they are both inexpensive to produce and are effective occlusive ingredients. It's generally believed, when properly refined, petrolatum has no known health concerns and is safe to use. Another concern is regarding the impact to the environment because both are derived from crude oil, a renewable resource.
Dimethicone is one of the best and most popular synthetic occlusive ingredients because it is inexpensive and easy to produce and it excels at forming a nice moisture barrier over the skin. Another reason for dimethicone's popularity is that is it is the only ingredient listed that has a greasy feeling when applied to the skin.
There is a wide variety of ingredients-many of them all-natural-that can provide the occlusive component of your moisturizer. As mentioned above, some of them have emollient or humectant properties as well. This gives you a great chance to mix various emollient, humectant, and occlusive agents for a great moisturizer that works for your skin's unique needs.
This is the second of three BEAUTY SCIENCE articles on types of ingredients in moisturizers. Click here if you missed Humectants. Next week we will discuss Emollients.
