Routines

Slugging: How Petroleum Jelly Repairs Your Skin Barrier Overnight

Slugging uses petroleum jelly to reduce water loss by 99% and repair your skin barrier overnight. Learn the method, who should try it, and who should skip it.

Slugging: How Petroleum Jelly Repairs Your Skin Barrier Overnight

A 2024 comprehensive review in the Journal of the American Academy of Dermatology confirmed that petrolatum is non-comedogenic — it does not clog pores. Meanwhile, a StatPearls clinical reference reports that petroleum jelly reduces transepidermal water loss by nearly 99%, compared to just 20-30% for most conventional moisturizers. Slugging — applying a thin layer of petroleum jelly as the final step of your nighttime routine — harnesses this dramatic difference to repair compromised skin barriers overnight.

Quick Summary:

  • Petroleum jelly reduces transepidermal water loss by up to 99%, far exceeding any other moisturizer
  • A 2024 JAAD review confirmed petrolatum is non-comedogenic despite common misconceptions
  • Slugging works by creating a physical barrier that lets deeper skin layers rehydrate the stratum corneum
  • Best for dry, dehydrated, or barrier-compromised skin; use cautiously on acne-prone skin
  • Apply a thin layer as the final step over your complete skincare routine

What Is Slugging?

Slugging is the practice of applying a thin layer of petroleum jelly (like Vaseline) as the last step of your nighttime skincare routine. The name comes from the "slug-like" sheen it leaves on your face. While it became a social media trend, the underlying practice has been used in dermatology for decades — petroleum jelly is one of the most studied and recommended occlusive agents in medical literature.

The concept is straightforward: after applying your serums and moisturizer, you seal everything in with a petroleum-based occlusive layer. This prevents moisture from evaporating while you sleep, allowing your skin's natural repair processes to work in an optimally hydrated environment.

The Science of Occlusion

Understanding why slugging works requires understanding how your skin loses moisture.

Your skin barrier constantly loses water through a process called transepidermal water loss (TEWL). When this barrier is healthy, TEWL stays at manageable levels. When the barrier is compromised — from over-exfoliation, retinoid use, harsh weather, or conditions like eczema — water loss accelerates, leaving skin dry, tight, and prone to irritation.

Petroleum jelly creates a semi-permeable barrier on the skin's surface that dramatically slows water evaporation. StatPearls clinical data shows it reduces TEWL by nearly 99%, while other occlusives only manage 20-30%. This isn't just sealing water in — it's creating conditions where the deeper skin layers can actively replenish moisture in the stratum corneum.

A 2016 study in the Journal of Allergy and Clinical Immunology discovered that petrolatum does far more than simply sit on the surface. It significantly upregulated antimicrobial peptides, increased key barrier proteins including filaggrin and loricrin, increased stratum corneum thickness, and reduced inflammatory T-cell infiltrates. The researchers concluded that petrolatum significantly modulates antimicrobial and barrier differentiation measures — it actively helps rebuild the barrier, not just protect it.

A 2025 study in the Journal of Clinical Medicine confirmed these findings, showing that petrolatum significantly reduced TEWL, decreased skin temperature and erythema, increased stratum corneum hydration, and improved skin elasticity.

Glossy occlusive balm texture

How to Slug Properly

Step 1: Complete Your Normal Routine

Slugging is the final step, not a replacement for your routine. Cleanse, apply your serums (hyaluronic acid, niacinamide), and apply your regular moisturizer. CeraVe Moisturizing Cream (around $16) with ceramides makes an excellent base layer under petroleum jelly.

Step 2: Apply a Thin Layer of Petroleum Jelly

Take a pea-sized amount of plain petroleum jelly (Vaseline or store brand) and warm it between your fingertips. Gently press — don't rub — a thin, even layer across your face. You want a light sheen, not a thick mask. A little goes a long way.

Step 3: Sleep on It

The petroleum jelly works overnight while your skin's natural repair cycle is most active. Use a pillowcase you don't mind getting slightly greasy, or switch to a silk pillowcase that's easier to wash.

Step 4: Cleanse in the Morning

Wash off the petroleum jelly with your morning cleanser. A gentle cleanser like CeraVe Hydrating Facial Cleanser (around $16) removes the occlusive layer without stripping the barrier benefits.

Who Should Try Slugging

Dry skin types: If your skin feels tight, flaky, or rough despite moisturizing, slugging addresses the underlying moisture loss that moisturizers alone can't fully control. See our dry skin guide.

Barrier-compromised skin: Over-exfoliation, aggressive retinoid use, or harsh weather can damage your barrier. Slugging accelerates recovery. Use it on skin cycling recovery nights for maximum barrier repair.

Retinoid users experiencing peeling: If retinol or tretinoin is causing dryness and flaking, slugging on off-nights helps your barrier recover faster between retinoid applications.

Winter dryness: Cold, dry air strips moisture from skin faster. Slugging during winter months provides an extra layer of protection against environmental dehydration.

Eczema and very sensitive skin: Dermatologists routinely recommend petroleum jelly for eczema management. The AAD lists it as a first-line moisturizer for atopic dermatitis.

Slugging routine product layers

Who Should Be Cautious

Acne-prone skin: The 2024 JAAD review confirmed that petrolatum itself is non-comedogenic. However, petroleum jelly traps everything underneath it — if you apply it over comedogenic products, heavy oils, or a product your skin reacts to, those ingredients stay in prolonged contact with your skin. If you're acne-prone, keep the routine under the slug simple: hydrating serum plus lightweight moisturizer only.

Oily skin in humid climates: If your skin already produces abundant oil and you live in a humid environment, adding an occlusive layer may feel excessive and contribute to miliaria (heat rash). Try slugging only on specific dry patches rather than the full face.

Over active ingredients: Never slug directly over retinoids, AHAs, BHAs, or benzoyl peroxide on the same night. The occlusion dramatically increases penetration and can cause severe irritation or chemical burns. Save slugging for recovery nights when no actives are applied.

Verdict: Slugging is one of the simplest, cheapest, and most scientifically supported skincare techniques available. A jar of petroleum jelly costs under $5 and outperforms expensive "overnight repair masks" at reducing water loss and supporting barrier recovery. The key is knowing when to use it and what to avoid layering underneath.

Slugging Alternatives

If the texture of petroleum jelly bothers you, these alternatives provide occlusive benefits (though none match petroleum jelly's 99% TEWL reduction):

Aquaphor Healing Ointment (around $15) — Contains petroleum jelly as the primary ingredient plus lanolin, panthenol, and glycerin. Slightly easier to spread and provides additional humectant benefits.

CeraVe Healing Ointment (around $15) — Similar to Aquaphor but includes ceramides and hyaluronic acid. A good option if you want occlusion with active barrier-repair ingredients.

Facial oils as a lighter alternative — Squalane or rosehip oil provide mild occlusion without the heavy feel. They reduce TEWL less effectively than petrolatum but more than creams alone.

For very dry skin, petroleum jelly remains the gold standard. For those who want something between a regular cream and full slugging, Aquaphor or CeraVe Healing Ointment are practical middle-ground options.

Frequently Asked Questions

Does petroleum jelly clog pores?

No. A 2024 comprehensive review in the Journal of the American Academy of Dermatology specifically addressed this misconception, confirming that petrolatum is non-comedogenic. However, trapping comedogenic products underneath it can contribute to breakouts.

How often should I slug?

For dry or barrier-compromised skin, nightly slugging is safe and effective. For normal skin, two to three nights per week is sufficient — particularly on skin cycling recovery nights. For oily skin, limit to once weekly or only during dry winter months.

Can I slug with retinol?

Never on the same night. Petroleum jelly dramatically increases ingredient penetration, which can cause severe irritation with retinoids. Use retinol on separate nights and slug only on recovery nights when no actives are applied.

Will slugging stain my pillowcase?

A thin layer shouldn't cause staining, but it can leave a greasy feeling on fabric. Use a designated pillowcase or switch to silk, which resists absorption better than cotton.

Is Vaseline the same as any petroleum jelly?

Yes. Vaseline is a brand name for 100% pure petroleum jelly. Store-brand petroleum jelly is chemically identical and equally effective. Ensure the product is 100% petrolatum without added fragrances or ingredients.

Can I slug my lips and under-eyes?

Yes. Both areas benefit significantly from occlusion. The under-eye area has thin skin prone to dehydration, and lips lack oil glands entirely. Apply a small amount of petroleum jelly to both areas as part of your slugging routine.

Does slugging help with wrinkles?

Slugging doesn't directly treat wrinkles (that requires retinoids, peptides, or vitamin C), but well-hydrated skin appears plumper, which temporarily minimizes fine line visibility. The barrier-repair benefits also help your active treatments work better on subsequent nights.

Is slugging just an overnight mask?

Essentially yes, but far cheaper and more effective. Many expensive "sleeping masks" contain small amounts of occlusive ingredients in a lighter base. Pure petroleum jelly provides superior occlusion for a fraction of the cost.

Can I slug during the day?

It's not practical for daytime use — the shiny appearance, incompatibility with makeup and sunscreen, and potential for collecting environmental debris make it an evening-only technique.

What should I put under the slug?

Keep it simple: a hydrating serum (hyaluronic acid or niacinamide) plus a ceramide-based moisturizer. Avoid heavy oils, active ingredients, or products with long ingredient lists that might cause reactions under occlusion.

How quickly does slugging show results?

Immediate hydration improvement is visible the morning after your first slug. Barrier repair benefits compound over one to two weeks of regular use. If you're recovering from over-exfoliation or retinoid damage, expect significant improvement within two to four weeks.

The Bottom Line

Slugging is dermatology's simplest barrier-repair technique: apply a thin layer of petroleum jelly over your routine at night to reduce water loss by up to 99%. It costs under $5, is backed by decades of research, and works better than any expensive overnight mask. Use it on recovery nights, keep actives on separate nights, and enjoy healthier, more hydrated skin.

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