Routine basics
Does slugging with petroleum jelly work?
Yes, for dry or damaged skin: a thin layer of petroleum jelly over moisturizer cuts overnight water loss better than almost anything, and it does not clog pores by itself. Skip it on oily skin and over strong actives.
- Moisturizer firstOn damp skin, the layer that does the work
- Thin petrolatum filmHolds the water in overnight
- Skip itOily or acne-prone skin, and over retinoids or acids
On this pageWhat a film of petroleum jelly actually does4
Quick answer
The bottom line
Slugging is an old dermatology remedy with a new name: a thin film of petroleum jelly over your night-time moisturizer to stop water escaping while you sleep. Petrolatum is the most effective common ingredient at reducing water loss through the skin, it does not cause allergies, and it does not block pores on its own, so for dry, tight, eczema-prone or winter-damaged skin it is cheap and useful. It is a poor idea on oily or acne-prone skin, where trapping oil and sweat under a film can worsen breakouts, and a bad idea over retinoids or acids, which it holds against the skin and intensifies. Apply a pea-sized amount to damp, moisturized skin, sleep on a clean pillowcase, and wash it off in the morning before sunscreen.
At a glance
Three things worth remembering
Section 01
What a film of petroleum jelly actually does
Petroleum jelly is an occlusive: it sits on the surface and physically slows water evaporating from the skin. Among common moisturizer ingredients it is the most effective at this by a wide margin, which is why it appears in guidance for dry skin, cracked heels and healing wounds. A classic physiology study found it does more than sit on top; it moves a little way into the outer layer and speeds recovery when the barrier has been damaged.[2][3]
Put a thin layer over a moisturizer at night and the moisturizer’s water and humectants stay in the skin instead of drying into the air. That is the whole trick. It adds no nutrients and no actives; it makes what you already applied work for longer.[3]
Section 02
Who benefits
Dry, tight, flaky skin, winter skin, skin that has been over-exfoliated or over-treated with retinoids and needs a rest, and eczema-prone skin all respond well. The Cochrane review of moisturizers in eczema found that regular use of almost any good emollient reduced flares and the need for steroid creams, and NHS guidance names ointments, which are essentially petrolatum, as the greasiest and most effective option for very dry skin.[4][5]
Dermatology guidance adds practical uses: on lips, around the nose during a cold, on heels and cuticles, and over minor scrapes to keep them moist. Petrolatum is hypoallergenic and non-comedogenic in testing, so the usual worries about "suffocating" the skin or blocking pores on its own are not borne out.[1]
Section 03
Who should skip it
Oily and acne-prone skin usually does worse: petrolatum itself does not block pores, but a film over an oily face traps sweat and sebum and bacteria against the skin all night, and people with acne commonly report more breakouts. The same trapped warmth and sweat can aggravate the yeast behind fungal acne, even though petrolatum is not something the yeast feeds on.[1]
Never slug over a retinoid, an exfoliating acid or high-strength vitamin C: the film holds them against the skin and increases how much gets in, which turns a tolerable product into a burn. Skip it in hot humid weather, over any infected or broken skin, and if you are prone to heat rash.[1][5]
Section 04
How to do it
Cleanse, apply your usual moisturizer to slightly damp skin, wait a minute, then warm a pea-sized amount of plain petroleum jelly between your fingers and press a thin film over the dry areas or the whole face. More is not better; a thick layer just ends up on the pillow. Use a clean pillowcase and wash your face in the morning, then sunscreen as usual.[1]
Two or three nights a week is plenty for maintenance; nightly is fine through a dry winter or a barrier-repair week off actives. If skin gets small bumps or breakouts, stop. If it is calmer and less tight in the morning, it is doing exactly what the evidence says it will.[3][4]
Your next step
Turn this into a practical plan
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