Occlusives are skincare ingredients that form a physical barrier on the skin’s surface to prevent water from evaporating. They don’t add moisture the way other ingredients do. Instead, they lock in the hydration already there. Petrolatum, the most effective occlusive available, reduces water loss through the skin by 98%. Most other occlusive ingredients only manage 20% to 30%.
How Occlusives Work
Your skin constantly loses water through evaporation, a process called transepidermal water loss (TEWL). When your skin barrier is healthy, this happens slowly enough that your skin stays hydrated. But dry air, harsh cleansers, skin conditions, and aging can all compromise that barrier, letting water escape faster than your body can replace it.
Occlusives work by sitting on top of the skin and creating a thin, oil-based film. This film physically blocks water molecules from passing through. Think of it like plastic wrap over a bowl of warm soup: the steam can’t escape, so the contents stay moist. The effect is temporary, lasting as long as the film stays intact, but it gives the skin time to repair itself and retain its natural hydration.
Common Occlusive Ingredients
Occlusive agents span several categories: mineral oils, silicones, vegetable oils, animal fats, wax esters, and sterols. Here’s how the most common ones compare.
- Petrolatum (petroleum jelly): The gold standard. It reduces water loss by up to 98% and is widely used in medical settings to protect healing skin. The tradeoff is a heavy, sticky feel and visible shine.
- Dimethicone (silicone): A lighter alternative that spreads easily and feels less greasy. It doesn’t block water loss as effectively as petrolatum, but it allows water vapor to pass through, which means it rarely causes heat rash or clogged pores. It also triggers fewer allergic reactions.
- Lanolin: Derived from sheep’s wool, lanolin is a strong occlusive that also softens skin. However, lanolin allergy has become more common. Patch testing data from a University of Copenhagen study showed the prevalence of lanolin allergy rose from 0.45% in 2004 to 1.81% in 2015 among dermatitis patients.
- Beeswax and plant waxes: Moderate occlusives often found in balms and salves. They create a semi-breathable barrier and are popular in natural formulations.
- Plant oils (coconut, jojoba, olive): These are lighter and less occlusive than petroleum-based options. Virgin coconut oil has been proposed as an occlusive for people with eczema because it forms a film on the skin while still allowing some gas and water vapor exchange. Jojoba oil feels the least greasy of the group because its structure closely mimics the skin’s own oils.
Petrolatum is roughly 170 times more effective at blocking moisture loss than olive oil. So while plant oils provide some occlusion, they’re in a different league when it comes to raw barrier protection.
Occlusives vs. Humectants vs. Emollients
Moisturizing products typically rely on three types of ingredients, each doing a different job. Humectants like glycerin and hyaluronic acid attract water molecules, pulling moisture from the environment and from deeper skin layers up to the surface. Emollients like fatty acids and ceramides fill in the gaps between skin cells, smoothing rough texture and making skin feel softer. Occlusives sit on top of everything and prevent that moisture from leaving.
None of these categories works as well alone as they do together. A humectant without an occlusive can actually make dryness worse in low-humidity environments, because it pulls water to the surface where it evaporates faster. An occlusive without a humectant just traps whatever moisture happens to be there, which may not be much. The most effective moisturizers combine all three: humectants to draw water in, emollients to smooth the skin, and occlusives to seal it all in place.
Occlusives for Eczema and Damaged Skin
People with eczema (atopic dermatitis) have a compromised skin barrier that loses water far faster than normal. Occlusive therapy, sometimes called “wet wrapping,” involves applying a thick occlusive layer and then covering it with damp bandages or clothing. Clinical reviews have found that wet occlusion consistently outperforms standard open treatment in patients with severe, acute, or chronic eczema.
Dry occlusion, where the skin is covered without dampening, has shown more mixed results. Some studies found improvement, while one actually showed better results in the control group. There is also a slightly higher risk of skin infections with occlusive therapy, since the warm, moist environment under the barrier can encourage bacterial growth. Temporary changes in cortisol rhythms have been noted as well, though these appear to be short-lived.
For everyday use, people with eczema often benefit from applying a petrolatum-based moisturizer immediately after bathing, while the skin is still damp. This traps the maximum amount of water against the skin.
Will Occlusives Clog Your Pores?
This is one of the biggest concerns people have, and the answer depends heavily on the specific ingredient. Petrolatum, despite its heavy feel, is generally considered non-comedogenic, meaning it doesn’t trigger acne in most people. Dimethicone is also well-tolerated and rarely causes breakouts.
Some occlusive ingredients do have a reputation for clogging pores. Acetylated lanolin and octyl palmitate are consistently flagged in comedogenicity testing. In one controlled trial, octyl palmitate increased comedone formation by more than 50% in every subject tested. On the other hand, products containing regular lanolin, avocado oil, and sunflower oil showed no significant comedone increase in the same study design.
Older ingredient lists from the 1980s and 1990s labeled many oils as comedogenic based on rabbit ear studies, which tend to overestimate clogging in human skin. More recent human trials have produced different results, so it’s worth being skeptical of blanket claims that all oils cause breakouts.
Slugging: The Overnight Occlusive Technique
Slugging is the practice of applying a thick layer of petroleum jelly as the final step in your nighttime skincare routine. The name comes from the shiny, slug-like appearance it gives your face. Cleveland Clinic dermatologist Melissa Kassouf recommends starting with clean skin: cleanse, exfoliate if needed, apply your regular moisturizer, then seal everything with the petroleum jelly layer.
One important caution: skip active ingredients like retinoids, alpha hydroxy acids, and beta hydroxy acids on nights you slug. The occlusive layer traps these actives against your skin, intensifying their effects and increasing the chance of irritation. Slugging works best during dry winter months when your skin loses moisture fastest. In warm, humid weather, it’s generally unnecessary.
If your skin is already oily, slugging is likely to cause problems. Oily skin already has a robust lipid layer, and adding more occlusion on top can lead to breakouts or a feeling of congestion. The technique is best suited for people with dry, dehydrated, or normal skin that needs extra barrier support.
Choosing the Right Occlusive for Your Skin
Your choice comes down to how much barrier protection you need versus how the product feels on your skin. Petrolatum offers the strongest protection but feels the heaviest. Dimethicone-based products feel lightweight and spread easily, making them better for daytime use or for people who dislike greasy textures. Plant oils fall somewhere in between, offering moderate occlusion with a more natural ingredient profile.
For severely dry or cracked skin, petrolatum is hard to beat. For daily facial moisturizing, a product with dimethicone as one of several ingredients will provide occlusion without the shine. For those who prefer plant-based options, layering a heavier wax or butter (like shea or beeswax) over a humectant serum can approximate the effect of petroleum-based products, though it won’t match the same level of water loss prevention.