Does slugging actually work?

Slugging is just a nickname for the oldest trick in moisturizing — applying an occlusive as the final step to seal the skin. Skincare moisturizers work through three ingredient types: occlusives, which sit on the stratum corneum and physically slow water from evaporating; humectants, which draw water into the epidermis; and emollients, which assimilate into the stratum corneum to smooth it. Slugging leans entirely on the occlusive mechanism: a layer of petrolatum (or a petrolatum-based ointment) on top of your routine dramatically reduces transepidermal water loss, so the hydration underneath stays in the skin overnight. It's the reason a 'slug' feels so effective on dry, tight skin — you're not adding water, you're stopping it from escaping.

• Study In the skin-barrier function model, occlusives, humectants, and emollients support the physical barrier by occluding the surface of the stratum corneum, drawing water from the dermis into the epidermis, and assimilating into the stratum corneum respectively, and moisturizers were shown to improve transepidermal water loss across several studies. ⁶
• Study Emollients and moisturizing creams are used to break the dry-skin cycle and maintain skin smoothness, with dryness frequently linked to impaired barrier function as seen in atopic skin, psoriasis, ichthyosis and contact dermatitis. ⁴

For the core claim — sealing in moisture and helping a damaged barrier — the evidence behind slugging's hero ingredient is genuinely strong. A landmark study found that Vaseline petroleum jelly didn't just sit on the surface and trap water; it permeated throughout the spaces between stratum corneum cells and actually accelerated barrier recovery after the barrier was disrupted. And when pure petrolatum was tested head-to-head against a fancier 'skin-identical lipids' cream on experimentally damaged human skin, there was no sign the sophisticated formula beat plain petrolatum at normalizing the barrier. In other words, the cheap slug really does the job — the occlusive is doing real barrier-supporting work, not just creating a greasy film.

• Study After acetone-induced barrier disruption in human volunteers, Vaseline petroleum jelly accelerated rather than impeded barrier recovery and was found throughout the stratum corneum interstices replacing intercellular bilayers — it neither forms nor acts like an impermeable epicutaneous membrane. ¹
• Study Comparing 'skin-identical lipids' in a petrolatum-rich cream base against pure petrolatum on detergent- and tape-stripped human skin (barrier recovery monitored as transepidermal water loss for 14 days) gave no indication the skin-identical-lipid cream was more efficient than pure petrolatum at promoting normalization. ⁵

A common worry is that sealing skin overnight 'suffocates' it or stops it from repairing. The data say otherwise. In controlled human studies on irritated skin (damaged with a harsh surfactant or tape-stripping), occlusion did not significantly delay barrier repair — and clinically, occlusion has long been used to help eczema and other barrier-disrupted conditions. Combined with the finding that petrolatum permeates the stratum corneum rather than forming an airtight seal, the picture is clear: a healthy or recovering barrier repairs fine underneath an occlusive. Skin doesn't 'breathe' through its surface in the way the myth implies.

• Study In controlled experiments on human skin irritated with sodium lauryl sulfate or tape-stripping, occlusion did not significantly delay repair of the water-permeability barrier as measured by transepidermal water loss, consistent with the well-known clinical benefit of occlusion in barrier-disrupted conditions like hand eczema. ³
• Study Petroleum jelly was shown to permeate the interstices at all levels of the stratum corneum rather than acting as an impermeable epicutaneous membrane, allowing normal barrier recovery despite its occlusive properties. ¹

Slugging shines for dry, dehydrated, flaky, wind- or winter-stressed, and barrier-compromised skin — exactly the situations where sealing in moisture and supporting repair pays off. This isn't a fringe idea: restoring barrier function with emollients is the first-line, evidence-based foundation of managing atopic dermatitis (eczema), and moisturizers are the standard tool for the dry, barrier-impaired skin seen in eczema, psoriasis and similar conditions. If your skin is tight, rough or over-exfoliated, a thin overnight occlusive over a plain moisturizer is a cheap, low-risk way to help it bounce back.

• Study In atopic dermatitis, where epidermal barrier defects are central, present prevention and treatment focus on restoration of epidermal barrier function, which is best achieved through the use of emollients. ⁷
• Study Moisturizers are used to break the dry-skin cycle in barrier-impaired conditions such as atopic skin, psoriasis, ichthyosis and contact dermatitis, with efficacy depending on dose and compliance. ⁴

Two honest cautions. First, acne: despite persistent rumors, petrolatum itself is not comedogenic and a thorough review dispels the myth that it causes acne — but slugging is more than the petrolatum. Occluding your entire face overnight can trap sweat, oil and debris against the skin, which for acne-prone, oily or congestion-prone people can mean clogged pores and breakouts; those skin types are better off spot-slugging dry areas, or skipping it. Second, actives: an occlusive dramatically increases how much of whatever is underneath gets into the skin, so slugging over a retinoid, an exfoliating acid or a strong vitamin C can turn a tolerable active into an irritating one. Slug over plain hydrators only — and keep your actives for nights you're not slugging.

• Study A comprehensive review of petroleum jelly details its safety profile and dispels misconceptions, including the myth that petrolatum is a cause of acne (comedogenicity). ²
• Study Because petroleum jelly permeates the stratum corneum interstices rather than sitting inertly on top, an occlusive layer meaningfully changes the skin-surface environment — supporting its use to seal in bland hydration while making it a poor partner for layering over irritating actives. ¹

• Slugging is moisture-sealing, not a treatment: the occlusive itself contributes no anti-aging, brightening or exfoliating action — it only locks in what's underneath, so results depend entirely on your skin's needs and what you applied first. ⁶
• Most of the rigorous evidence is for occlusives/petrolatum and barrier repair generally, not for 'slugging' as a branded overnight routine — the practice is an application of well-established occlusive science rather than a separately trialed intervention. ⁵
• It's the wrong tool for acne-prone, oily or congestion-prone skin: while petrolatum itself isn't comedogenic, full-face overnight occlusion can aggravate congestion for those skin types. ²

• A genuine occlusive base — the active part of slugging is the occlusive — petrolatum (petroleum jelly) is the gold standard; petrolatum-rich ointments (Aquaphor, CeraVe Healing Ointment) and lanolin-type balms also qualify. A light lotion is not a slug.
• Fragrance-free + minimal extras — you're sealing everything underneath against your skin all night, so a simple, fragrance-free occlusive lowers the odds of irritation or sensitization.
• Right for your skin type — best for dry, dehydrated, flaky or barrier-compromised skin. If you're acne-prone, oily or congestion-prone, skip full-face slugging — spot-slug dry patches instead.
• Nothing active to seal over — slug over bland hydrators (hyaluronic acid, glycerin, ceramide moisturizer) only — not over a retinoid, acid or strong vitamin C, since occlusion boosts their penetration and irritation.
• An amount you can sleep in — a thin layer is enough; a thick one is messy, transfers to pillows, and isn't more effective. Apply to slightly damp (clean, not wet) skin as the final step.

Does slugging actually do anything, or is it a TikTok myth?

It genuinely works for sealing in moisture and supporting a dry or damaged barrier. Occlusives like petrolatum reduce transepidermal water loss, and petrolatum specifically permeates the stratum corneum and accelerates barrier recovery rather than just sitting on top. What it doesn't do is treat anything on its own — it locks in whatever you applied underneath, so think of it as a moisture seal for dry/compromised skin, not an active step. ¹⁶

Is slugging bad for your skin or pores — doesn't it suffocate the skin?

For most skin types, no — the 'skin can't breathe' idea is a myth. Controlled studies show occlusion doesn't delay barrier repair, and petrolatum permeates the stratum corneum rather than forming an airtight film. The real caveat is acne: petrolatum itself isn't comedogenic, but occluding the whole face overnight can trap oil and debris, so acne-prone, oily or congestion-prone skin should skip full-face slugging or only spot-treat dry areas. ³²

Who should slug, and who shouldn't?

Slug if your skin is dry, dehydrated, flaky, over-exfoliated or barrier-compromised — emollients are the first-line, evidence-based way to restore a damaged barrier, and an overnight occlusive is a cheap version of that. Don't slug if you're acne-prone or oily (occlusion can aggravate congestion). Either way, slug over plain hydrators only, never over a retinoid, acid or strong vitamin C, since occlusion increases their penetration and can cause irritation. ⁷¹

What should I use to slug, and how?

Use a true occlusive — petroleum jelly (Vaseline) is the gold standard, and petrolatum-rich ointments like Aquaphor or CeraVe Healing Ointment work too; fragrance-free is best. Apply a thin layer as the very last PM step over clean, slightly damp skin and a plain moisturizer or hydrating serum (hyaluronic acid, glycerin, ceramides). A thin layer is plenty — more just transfers to your pillow without working better. ⁵⁶

1. 1

   Effects of petrolatum on stratum corneum structure and function

   J Am Acad Dermatol · 1992

2. 2

   Petroleum jelly: A comprehensive review of its history, uses, and safety

   J Am Acad Dermatol · 2024

3. 3

   Skin permeability barrier and occlusion: no delay of repair in irritated human skin

   Contact Dermatitis · 1996

4. 4

   Role of topical emollients and moisturizers in the treatment of dry skin barrier disorders

   Am J Clin Dermatol · 2003

5. 5

   Skin-identical lipids versus petrolatum in the treatment of tape-stripped and detergent-perturbed human skin

   Acta Derm Venereol · 2000

6. 6

   The Skin Barrier and Moisturization: Function, Disruption, and Mechanisms of Repair

   Skin Pharmacol Physiol · 2023

7. 7

   Atopic dermatitis

   Lancet · 2016