Barrier & Balm

What Is Slugging (and Should You Try It)?

Slugging seals your skin overnight under a layer of occlusive like petroleum jelly. It genuinely helps dry, compromised skin hold water — and it can just as genuinely break out oily skin.

By Stephen V.Last updated How we pick

Slugging is the practice of sealing your skin overnight under a thin layer of an occlusive — most famously plain petroleum jelly — applied as the last step of your evening routine. The goal is to trap water in while you sleep so you wake up with softer, more hydrated skin. Like a lot of viral skincare, it is a rebrand of something dermatologists have done for years, and like a lot of viral skincare, it is genuinely great for some people and a bad idea for others. Whether you should try it comes down almost entirely to your skin type. Here is how it works, who it helps, and who should leave it alone.

How slugging works

Moisturizers do their job through three kinds of ingredient: humectants that pull water into the skin, emollients that soften and smooth, and occlusives that form a physical barrier to slow water from evaporating out. Slugging is occlusion turned up to its logical extreme. By coating the skin in a thick occlusive like petrolatum, you dramatically reduce transepidermal water loss — the constant, invisible evaporation of moisture through the skin — overnight. Importantly, an occlusive does not add moisture itself; it locks in the water and products already there. That is why slugging works best over a routine that has already hydrated the skin, sealing that hydration in rather than trapping a dry surface.

The right way to do it

The technique is simple. Do your normal evening routine first — cleanse, then apply any hydrating serums and your usual moisturizer, ideally while skin is still slightly damp so there is water to seal in. Then smooth a thin film of petroleum jelly or a similar occlusive over the top as the final layer. Use an old pillowcase, because the balm transfers, and cleanse gently in the morning. The one rule that matters most: keep what is underneath gentle. Because an occlusive increases how much of whatever is below it penetrates the skin, slugging over hydration is smart and slugging over a retinoid or an exfoliant can turn a tolerable active into an irritating one. Seal in moisture, not treatment.

Who benefits

Slugging is a strong fit for dry, dehydrated and barrier-compromised skin. If your skin is flaky, tight, or roughed up by cold, wind or over-exfoliation, an occlusive seal gives it the calm, humid environment it needs to recover, and it pairs naturally with barrier-supporting ingredients like ceramides underneath. It is also useful in harsh winter weather or dry indoor heating, where water loss speeds up. In fact, sealing a damaged barrier with an occlusive is one of the recognized moves for helping it heal — our guide on how to repair your skin barrier covers where it fits in a fuller recovery plan. For genuinely dry skin, slugging is not a gimmick; it is one of the more effective things you can do.

Who should skip it

Oily and acne-prone skin should be cautious, and often should skip slugging entirely. Petrolatum itself is not comedogenic, but sealing an occlusive over skin that already produces excess oil traps that oil, sweat and bacteria against the surface, which can worsen congestion and trigger breakouts. If your skin runs oily, you may find slugging leaves you shinier and more broken out, not more radiant. At most, oily skin can spot-slug a dry patch rather than coating the whole face. Skin that is already balanced and comfortable does not need it either — there is nothing to gain from sealing skin that is not losing water in the first place. When in doubt, our routine for dry skin shows how to work in an occlusive step only where it earns its place.

How often, and what to expect

Slugging is a tool, not a nightly ritual. Dry skin might benefit a few nights a week, or through a rough seasonal stretch; balanced skin rarely needs it at all. The result you should expect is softer, more comfortable, better-hydrated skin the next morning — not a dramatic transformation and not any brightening, exfoliating or anti-aging effect, because an occlusive does none of those things. Manage expectations accordingly: slugging is very good at one narrow job, holding water in, and does nothing beyond it. If your skin is chronically, severely dry despite good moisturizing and the occasional slug, that is worth raising with a dermatologist, since persistent dryness can point to an underlying condition.

The bottom line

Slugging is a legitimate, effective technique wearing a trendy name. Sealing your skin overnight with a plain occlusive genuinely helps dry, dehydrated and barrier-damaged skin hold onto water, and it costs next to nothing. It is equally capable of breaking out oily and acne-prone skin, which is why the honest advice is skin-type-specific: a great occasional step for the dry, a risky one for the oily, and unnecessary for the already-balanced. Do it over hydration rather than actives, keep it occasional, and let your skin’s dryness — not a trend — decide whether it is worth your pillowcase.

General guidance, not medical advice. Barrier & Balm is written by a skincare enthusiast, not a dermatologist. For a diagnosis, a reaction, or a prescription active like tretinoin, see a qualified professional. Introduce any new active slowly and patch-test first.

Frequently asked questions

What do you actually put on your skin to slug?

Most people use plain petroleum jelly, because it is a highly effective occlusive that seals water into the skin, is inexpensive, and rarely irritates. Other thick balms and occlusive ointments work on the same principle. The key trait is occlusivity — the ability to form a physical barrier that slows water loss — not any active ingredient. Petrolatum itself does not moisturize so much as prevent moisture from escaping.

Does slugging clog pores or cause breakouts?

It can, particularly on oily or acne-prone skin. Petrolatum itself is not comedogenic, but sealing an occlusive over skin traps oil, sweat and whatever is underneath, which can worsen congestion and breakouts in people already prone to them. That is exactly why oily and acne-prone skin is usually advised to skip it, or at most spot-treat dry patches. Dry skin, which lacks that excess oil, tends to tolerate it far better.

Should I put actives under my slugging layer?

Generally no. An occlusive dramatically increases how much of whatever is underneath penetrates the skin, so slugging over a retinoid or an exfoliant can turn a normally tolerable active into an irritating one. Keep the layers under your occlusive gentle — hydrating serums and a plain moisturizer — and save actives for nights you are not slugging. When in doubt, seal in hydration, not treatment.

How often should I slug?

As often as your skin genuinely needs it, which for most people is occasional rather than nightly. Dry, flaky or wind-and-cold-battered skin might benefit a few nights a week or during a rough winter stretch; balanced skin rarely needs it at all. There is no benefit to slugging skin that is already comfortable and well hydrated. Let dryness, not habit, decide.

Is slugging just a trendy name for something basic?

Essentially, yes. Sealing dry skin with an occlusive ointment is a long-standing dermatology tactic, especially for very dry or barrier-compromised skin — slugging is the viral rebrand of it. That does not make it fake; occlusives really do reduce water loss and help skin recover. The name is new, the technique is old and well established.

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