What Is an Occlusive Ingredient?
An occlusive is a substance that physically blocks the passage of water vapor across the skin surface. Unlike humectants, which attract water into the skin, or emollients, which fill in the gaps between skin cells, occlusives work by forming a semi-impermeable film that slows or prevents transepidermal water loss (TEWL). They do not add moisture — they conserve it.
The occlusive effect is a purely physical phenomenon. The film-forming occlusive molecule sits on top of the stratum corneum, too large to penetrate, and reduces the surface area through which water vapor can escape. The denser and more continuous this film, the greater the TEWL reduction. Petrolatum, which creates a near-complete film with minimal gaps, achieves up to 99% TEWL reduction. Lighter occlusives like squalane create a thinner, more permeable film with a correspondingly lower — though still meaningful — TEWL reduction.
Understanding occlusives as physical barrier agents rather than moisturizing ingredients changes how you use them. Their job is not to nourish or repair — it is to preserve the gains made by the ingredients applied underneath. This is why occlusive application sequence matters: they must always come last in any routine.
How Occlusives Prevent Transepidermal Water Loss
Transepidermal water loss is the passive diffusion of water vapor from the deeper skin layers through the stratum corneum and into the ambient environment. In healthy skin with an intact barrier, the lipid matrix of the stratum corneum limits TEWL to approximately 3–5 g/m²/hour. In compromised skin — with disrupted ceramide ratios, physical damage, or inflammatory conditions — TEWL can increase to 30–75 g/m²/hour or more.
Occlusives address this elevated TEWL directly. A continuous petrolatum film reduces the water vapor pressure gradient across the stratum corneum by creating an additional impermeable layer above it. This both reduces water loss and creates a local high-humidity microenvironment at the skin surface — which in turn accelerates the skin's endogenous barrier repair mechanisms. Studies on wound healing and barrier recovery consistently show faster recovery under occlusion than in open-air conditions.
The clinical implication is significant: for a compromised barrier, even a basic petrolatum application creates conditions that support faster lipid synthesis and barrier reconstitution. The occlusive does not do the repair — the skin does — but it creates the optimal environment for that repair to occur.
Types of Occlusives: From Petrolatum to Plant Oils
Occlusives range from highly effective synthetic and mineral-derived molecules to natural plant-based alternatives with varying performance profiles. The key variables are TEWL reduction efficacy, comedogenic potential, texture, and skin compatibility.
| Occlusive | TEWL Reduction | Comedogenic Risk | Texture | Best For |
|---|---|---|---|---|
| Petrolatum | Up to 99% | None (non-comedogenic) | Heavy, greasy | Severely compromised barrier, wound care, winter skin |
| Dimethicone | ~40–50% | Very low | Light, silky | Acne-prone or oily skin; daytime use |
| Squalane | ~20–30% | Very low (0–1) | Dry-touch oil | Acne-prone, oily, or combination skin; lightweight option |
| Shea Butter | ~40–60% | Low–moderate (0–2) | Rich, buttery | Dry and mature skin; body use; non-facial application |
| Lanolin | ~70–80% | Low | Waxy, thick | Severely dry skin; chapped lips; not for lanolin-sensitive individuals |
The Correct Layering Order: Humectant, Emollient, Occlusive
The most effective moisturization protocol follows a three-layer logic that mirrors the skin's own moisture management system. Each layer performs a distinct function, and the order is non-negotiable — applying an occlusive before a humectant traps nothing, because there is no moisture to retain yet.
Layer 1 — Humectant: Applied to damp skin post-cleanse, the humectant (hyaluronic acid, glycerin, panthenol) draws water into the outer skin layers and binds it temporarily. This is the water-loading step.
Layer 2 — Emollient: Applied over the humectant while still damp, the emollient (ceramides, fatty acids, plant oils) fills in the gaps between corneocytes, softens skin texture, and begins to slow the evaporation rate while providing lipid replenishment.
Layer 3 — Occlusive: Applied last, the occlusive seals the entire moisture complex beneath a physical film, dramatically reducing evaporation and maintaining the high-humidity microenvironment that allows the deeper layers to stay hydrated. Apply while skin is still slightly tacky from the emollient for best adhesion and coverage.
When to Use an Occlusive (and When to Skip It)
Occlusives are most beneficial in the PM routine, where you have several hours for the sealed moisture environment to support repair without the practical concerns of texture under makeup. PM application also aligns with the skin's natural circadian repair cycle — barrier repair and lipid synthesis are upregulated during sleep.
AM occlusive use is possible but requires a lighter formulation — dimethicone or squalane sit more comfortably under SPF and makeup than petrolatum. For most people, a well-chosen ceramide moisturizer with emollient and mild occlusive properties (shea, dimethicone) is sufficient for daytime use without the need for a separate occlusive layer.
Which Occlusive Is Right for Your Skin Type?
The right occlusive depends on both efficacy needs and skin tolerance. For severely compromised or very dry skin, petrolatum provides the most complete TEWL barrier and should be the first choice. For normal-to-dry skin, a shea-based moisturizer or lanolin-containing product provides substantial occlusion with a more cosmetically acceptable texture.
For acne-prone or oily skin, squalane or a dimethicone-containing moisturizer provides meaningful occlusion without comedogenic risk. Squalane is particularly well-suited here — it is a stable, non-irritating lipid that mimics the skin's own sebum and has a comedogenic rating of 1 on a scale of 0–5. Applied in a thin layer over a water-based moisturizer, it provides the sealing effect without the heaviness of traditional occlusives.
For sensitive skin with known ingredient intolerances, petrolatum is paradoxically the safest choice — it is inert, hypoallergenic, and contains no botanicals, fragrances, or actives that could trigger a reaction. The apparent heaviness of petrolatum is not correlated with irritation potential; it is one of the most well-tolerated cosmetic ingredients across all skin types.
Top-Rated Occlusive Products
Frequently Asked Questions
What is the most effective occlusive for skin barrier repair?
Petrolatum (Vaseline) is the most effective topical occlusive, reducing transepidermal water loss by up to 99%. It is inert, non-allergenic, and non-comedogenic despite its thick texture. For those who find it too heavy, dimethicone is the next most effective option with a lighter feel.
Is Vaseline (petrolatum) safe to put on your face?
Yes. Cosmetic-grade petrolatum is highly purified, inert, and has one of the best safety profiles of any skincare ingredient. It does not penetrate the skin, cannot clog pores, and does not cause allergic reactions. It has been used in wound care and dermatology for over 150 years.
Can occlusives cause breakouts or clog pores?
Petrolatum and dimethicone are non-comedogenic and do not clog pores or cause breakouts. Some plant-based occlusives (coconut oil, cocoa butter) have higher comedogenic ratings and may trigger breakouts in acne-prone individuals. If you are acne-prone, choose petrolatum, squalane, or dimethicone-based occlusives.
Should I use an occlusive every night?
Daily occlusive use is beneficial for dry, sensitive, or barrier-compromised skin. For normal or combination skin, an occlusive as the final PM step 3–5 nights per week is typically sufficient. In winter or dry climates, nightly use becomes more important to counteract increased TEWL from environmental conditions.
What is the difference between an occlusive and an emollient?
An occlusive forms a physical film on the skin surface that prevents water evaporation — it does not penetrate. An emollient penetrates into the stratum corneum and fills the gaps between corneocytes, softening skin texture. Both are needed: emollients smooth and soften, occlusives seal and protect.
