Essential Components of a Moisturizer - Part 3: Occlusives

When it comes to skincare, the quest for hydrated, healthy skin often leads us to various moisturizers promising deep nourishment and hydration. But what exactly sets a good moisturizer apart from the rest? The answer lies in understanding the role of occlusives in skincare formulations. Welcome to part 3 of the series, Essential Components of a Moisturizer: Occlusives.

Why Does a Moisturizer Need an Occlusive?

Occlusives play a crucial role in skincare by forming a barrier on the skin's surface, preventing water loss through evaporation (transepidermal water loss) and sealing in moisture. This sealing effect helps maintain hydration levels in the skin, leading to a smoother, more supple complexion. Without an occlusive component, moisturizers may struggle to lock in moisture effectively, resulting in drier, dehydrated skin despite regular application.

So, what are the benefits of occlusives in skin care?

1. Intensive Hydration: Occlusives create a protective layer on the skin, reducing transepidermal water loss (TEWL) and allowing the skin to retain moisture more efficiently.

2. Enhanced Skin Repair: By creating a barrier that shields the skin from external aggressors, occlusives support the skin's natural healing process, especially beneficial for individuals with chronically dry skin, skin barriers.

3. Improved Skin Texture: The smoothing effect of occlusives helps soften rough patches, soothe irritation, and restore the skin's elasticity, promoting a healthier skin texture overall.

Effective Occlusive Ingredients and Their Benefits

Several ingredients (some synthesized and some natural) stand out as potent occlusives in skincare formulations due to their ability to form an effective barrier and lock in moisture:

1. Petrolatum: Known for its superior occlusive properties, petrolatum forms a protective seal on the skin's surface, preventing water loss and enhancing skin hydration.

2. Dimethicone: A silicone-based occlusive, dimethicone creates a smooth barrier on the skin, keeping moisture locked in while providing a silky, non-greasy feel.

3. Mineral Oil: Lightweight yet effective, mineral oil forms a protective layer on the skin, reducing TEWL and restoring moisture balance.

4. Beeswax: With its natural emollient and occlusive properties, beeswax helps soften the skin, lock in moisture, and protect against environmental stressors.

Why Not All Plant Oils Occlusive

While plant oils and butters are popular in skincare for their rich texture and nourishing benefits, not all plant oils and butters function as fully occlusive. The occlusive properties of an ingredient depend on its molecular structure and how effectively it can create a barrier on the skin. Some plant butters and oils, despite being excellent emollients, do not form a strong enough barrier to qualify as fully occlusive, making them better suited for moisturizing rather than sealing in moisture. Most plant oils and some butters are partly metabolized by skin and their constituents integrated into the skin barrier. This is beneficial to skin in other ways, but it also means that these ingredients would be considered semi-occlusive, since they are not sitting inertly on the top of skin forming a protective seal (like paraffin oil would). 

After my research, I consider there to be differing levels of occlusivity. Waxes like beeswax, candelilla wax, petrolatum and mineral oil would be more occlusive. Plant oils that are lower in oleic acid content (like rosehip, grapeseed, and evening primrose) would be less occlusive. When looking to use natural plant butters as the occlusive agent in a moisturizer, more oleic acid content may correlate to better occlusive function.

Incorporating occlusives into your skincare routine significantly enhances hydration, protect the skin's barrier, and promote overall skin health. By choosing products with effective occlusive ingredients, you can ensure that your skin stays moisturized, supple, and resilient against daily stressors.