What Is Slugging? Benefits, Risks, and How to Do It Right

Slugging has taken over skincare conversations in recent years, moving from a niche K-beauty practice to a viral trend across social media. The concept is simple: apply a thin layer of an occlusive product, typically petroleum jelly, as the very last step of your nighttime skincare routine. You wake up with skin that feels intensely hydrated and smooth. But is slugging actually good for your skin, and is it right for everyone?

In this guide, we will cover the science behind why slugging works, its real benefits, the potential risks, who should try it (and who should not), the proper technique, and alternatives for those who prefer not to use petroleum jelly.

What Exactly Is Slugging?

Slugging is the practice of sealing your nighttime skincare routine with an occlusive layer, most commonly plain petroleum jelly (like Vaseline or Aquaphor). The name comes from the shiny, slightly slimy appearance your face takes on after application, resembling a slug's trail. While the name is new, the concept is not. Dermatologists have recommended petroleum jelly for barrier repair and wound healing for decades, and the Korean skincare community popularized the practice of using it as a final skincare step long before it went viral on social media.

The core principle behind slugging is occlusion: creating a physical barrier on the skin's surface that prevents moisture from evaporating.

The Science: How Slugging Works

To understand why slugging is effective, you need to understand transepidermal water loss, commonly abbreviated as TEWL. Your skin constantly loses water to the environment through evaporation. When your skin barrier is healthy, TEWL stays at a manageable level. When it is compromised (from over-exfoliation, harsh weather, irritating products, or certain skin conditions), TEWL increases, leading to dehydration, tightness, flaking, and increased sensitivity.

Petroleum jelly is the most effective occlusive ingredient available. Research published in the Journal of Cosmetic Science found that petroleum jelly reduces TEWL by up to 98 percent, compared to approximately 20 to 30 percent for most moisturizers. By locking the moisture from your previous skincare steps (serums, essences, moisturizers) into the skin, slugging creates an optimal environment for overnight hydration and repair.

It is important to clarify what slugging does not do: it does not add moisture to the skin. Petroleum jelly is purely occlusive. It traps what is already there. This is why applying it over hydrating layers (hyaluronic acid, glycerin-based serums, a good moisturizer) is essential. Slugging over dry, bare skin would simply seal in dryness.

Benefits of Slugging

Intense Overnight Hydration

The most immediate and noticeable benefit of slugging is significantly improved skin hydration by morning. By preventing overnight moisture loss, your skin retains the hydration from your entire evening routine. Many people report that their skin feels plumper, softer, and more supple the morning after slugging, with a noticeable reduction in dry patches and flaking.

Barrier Repair

Slugging is particularly valuable for compromised skin barriers. When your barrier is damaged, it cannot retain moisture effectively, creating a cycle where dehydration worsens barrier damage, which further increases dehydration. Occlusion breaks this cycle by artificially providing the moisture retention that your barrier currently cannot. A study in the British Journal of Dermatology demonstrated that occlusive dressings (including petroleum-based products) accelerated skin barrier recovery after experimental disruption.

If you are recovering from over-exfoliation, retinol irritation, harsh weather damage, or a skin condition like eczema, slugging can fast-track barrier recovery. This is why many dermatologists recommend petroleum jelly as part of the recovery protocol for patients experiencing medication-induced skin irritation.

Enhanced Product Absorption

The occlusive layer created by slugging keeps active ingredients from your serums and treatments in contact with the skin for longer, rather than evaporating or being rubbed off onto your pillow. This can enhance the effectiveness of hydrating ingredients like hyaluronic acid, niacinamide, and peptides. However, this enhanced absorption is a double-edged sword when it comes to potentially irritating actives, which we will address in the risks section.

Skin Smoothness and Texture

Regular slugging can improve skin texture by addressing dehydration-related roughness. When skin cells are adequately hydrated, they lie flat and reflect light evenly, giving the appearance of smoother, more refined skin. This is not a permanent structural change, but the cosmetic improvement can be significant for people dealing with dry, rough, or flaky skin.

Risks and Potential Downsides

Clogged Pores for Oily and Acne-Prone Skin

This is the most significant concern with slugging. While petroleum jelly itself is technically non-comedogenic (it does not penetrate pores), the occlusive environment it creates can trap sebum, bacteria, and dead skin cells against the skin's surface. For people with oily or acne-prone skin, this can lead to clogged pores, milia (small white bumps), and breakouts.

If you are prone to congestion or have active acne, slugging your entire face is generally not recommended. Some people with combination skin find success with targeted slugging, applying the occlusive only to dry areas (cheeks, around the nose, lips) while avoiding the T-zone.

Trapping Irritating Ingredients

Because slugging enhances the contact time and penetration of everything underneath it, applying an occlusive over potentially irritating actives can amplify their effects to an uncomfortable degree. You should never slug over retinoids (retinol, tretinoin, adapalene), chemical exfoliants (AHAs like glycolic acid, BHAs like salicylic acid), benzoyl peroxide, or vitamin C at high concentrations. The occlusive layer can intensify irritation, cause burning, and worsen redness. Save slugging for nights when your routine consists only of gentle, hydrating products.

The Mess Factor

There is no way around it: sleeping with a layer of petroleum jelly on your face is messy. It transfers to pillowcases, can feel heavy and suffocating for some people, and requires thorough cleansing in the morning. Using a silk pillowcase and applying a thinner layer can minimize this, but slugging will never be the neatest skincare step in your routine.

Who Should Try Slugging

Dry skin types: Slugging is tailor-made for naturally dry skin that struggles with moisture retention. It is the most effective at-home method for combating overnight dehydration.
Anyone with a compromised barrier: If your barrier has been disrupted by over-exfoliation, harsh products, or environmental stress, slugging accelerates recovery.
People in dry or cold climates: Low humidity environments dramatically increase TEWL. Slugging counteracts this by locking moisture in during the driest hours (overnight, with heating on).
Those on drying medications: Isotretinoin (Accutane), topical retinoids, and certain other medications cause significant dryness. Dermatologists frequently recommend occlusive products for these patients. Building a supportive routine for dry and sensitive skin with slugging can make medication side effects more manageable.
Eczema sufferers: Petroleum jelly is a first-line recommendation from the National Eczema Association for managing eczema-related dryness and barrier dysfunction.

Who Should Avoid Slugging

Oily and acne-prone skin: The occlusive environment can worsen congestion and trigger breakouts.
People with fungal acne (malassezia folliculitis): While petroleum jelly is not a food source for malassezia yeast, the warm, occluded environment it creates can promote fungal growth.
Anyone with active inflammatory acne: Trapping bacteria and sebum against actively inflamed skin is counterproductive.
People using retinoids or exfoliants that night: The enhanced penetration will increase irritation significantly.

The Proper Technique

If you have decided to try slugging, here is how to do it correctly for maximum benefit and minimum mess.

Step-by-Step Process

Cleanse thoroughly. Start with a clean face. Double cleanse if you wore sunscreen or makeup. Any dirt, debris, or irritating residue left on the skin will be sealed in.
Apply your hydrating layers. This is the most important step. Apply a hydrating toner or essence, a serum with hyaluronic acid or niacinamide, and a moisturizer. These are the layers providing the actual moisture that slugging will lock in. Remember: no actives like retinol, acids, or vitamin C.
Wait a few minutes. Let your moisturizer absorb partially before applying the occlusive. This prevents everything from sliding around.
Apply a thin layer of petroleum jelly. Warm a pea-sized amount between your fingertips and press it gently over your face. You do not need a thick layer. A thin, even coat is sufficient to create the occlusive barrier. Focus on areas that tend to be driest (cheeks, forehead, around the nose).
Use a designated pillowcase. Silk or satin pillowcases work best, as they absorb less product than cotton. Some people use a clean towel over their pillow instead.
Cleanse well in the morning. An oil-based cleanser followed by a gentle water-based cleanser (double cleanse) effectively removes petroleum jelly without harsh scrubbing.

How Often to Slug

Slugging does not need to be a nightly practice for most people. Many find that two to three nights per week is enough to maintain hydration and support barrier health. During particularly dry weather, after a flight, or while recovering from a compromised barrier, you might increase frequency. During warmer, more humid months, you may not need to slug at all.

Listen to your skin. If it feels adequately hydrated and your barrier is healthy, your regular moisturizer may be sufficient.

Alternatives to Petroleum Jelly

If you prefer not to use petroleum jelly, several alternatives provide occlusive benefits, though none match its 98 percent TEWL reduction.

Aquaphor Healing Ointment

Aquaphor is about 41 percent petroleum jelly, combined with lanolin, panthenol, and glycerin. It provides strong occlusion with added moisturizing and healing benefits. Many people find it slightly easier to spread and less purely "greasy" than plain petroleum jelly. It is an excellent middle ground between a heavy cream and full slugging.

Ceramide-Rich Barrier Creams

Ceramide-based creams provide occlusion through a combination of emollient and occlusive ingredients rather than relying solely on petroleum. Products containing ceramides, cholesterol, and fatty acids mimic the skin's natural lipid barrier. They are less occlusive than petroleum jelly but more elegant to use and less likely to cause issues for breakout-prone skin. They represent the best option for people who want some of the benefits of slugging without the full commitment.

Squalane Oil

Squalane is a lightweight, non-comedogenic oil that provides moderate occlusion. It is well-tolerated by most skin types, including oily skin, and mimics the skin's natural sebum. While it does not prevent TEWL as effectively as petroleum jelly, it offers enough occlusion to boost hydration without the heaviness or mess.

Shea Butter and Plant-Based Balms

For those who prefer plant-derived ingredients, shea butter and balms based on plant waxes (like candelilla or carnauba) provide meaningful occlusion. These options tend to be well-suited for body slugging and can work on the face for dry skin types. However, check for added fragrances or essential oils that could cause irritation.

Slugging is not a universal solution, but for the right skin type and in the right conditions, it is one of the most effective methods for combating dehydration and supporting barrier repair. The key is understanding whether your skin will benefit from it and applying the technique correctly.

Frequently Asked Questions

Can I slug if I have combination skin?

Yes, with a targeted approach. Instead of applying the occlusive layer to your entire face, focus on the areas that tend to be dry, such as the cheeks, jawline, and around the nose. Avoid the T-zone (forehead, nose, chin) if it tends to be oily or congestion-prone. This selective technique, sometimes called "partial slugging," lets you reap the hydration benefits where you need them without risking breakouts in your oilier zones. Start with one to two nights per week and observe how your skin responds before increasing frequency.

Is petroleum jelly safe for the skin?

Yes. Pharmaceutical-grade petroleum jelly (like Vaseline) has an excellent safety record spanning over a century of use. It is non-toxic, non-allergenic, and non-comedogenic, meaning the molecules are too large to enter pores. The American Academy of Dermatology recommends petroleum jelly for wound care, eczema management, and lip care. Concerns about petroleum jelly being "toxic" or containing harmful contaminants apply to industrial-grade petrolatum, not the purified pharmaceutical-grade product found in consumer skincare. It is one of the most thoroughly tested and safest ingredients in dermatology.

Can I slug during the day?

Technically, yes, but it is not practical or recommended for most people. Daytime slugging makes it difficult to apply sunscreen or makeup on top, gives a very shiny appearance, and collects dust and environmental debris against your skin. If you need occlusive protection during the day (for example, in extremely cold, windy weather), a heavy ceramide cream or a lighter occlusive like squalane oil is a better choice. Save petroleum jelly slugging for nighttime when the product can work undisturbed for several hours.

How do I know if slugging is working for my skin?

Signs that slugging is benefiting your skin include waking up with plumper, softer, more hydrated skin; reduced flaking and dry patches; less tightness and discomfort; and an overall improvement in skin smoothness within the first one to two weeks. Signs that slugging is not right for your skin include new breakouts (especially small closed comedones or whiteheads), increased oiliness, milia formation, or a feeling of congestion. Give it at least three to four sessions before deciding, but stop immediately if you experience significant new breakouts or irritation.