What exactly is slugging?

Slugging is a K-beauty trend of generously applying a petroleum-based product as the final step in your routine, to help lock and seal in your skincare products overnight, and then washing it off with a cleanser the next day. “Slugging is a great skincare technique in the wintertime for those with dry or sensitive skin,” says Shari Marchbein, MD, a board-certified dermatologist and clinical assistant professor of dermatology at NYU School of Medicine. “Petroleum jelly is an occlusive that is not only amazing at soothing irritated skin and promoting wound healing, but it can act as a protective barrier for the skin, too.”

What are the benefits of slugging?

Baby soft, seriously hydrated skin, anyone? Slugging creates a seal over the skin, prevents transepidermal water loss, and protects and repairs your skin’s natural lipid barrier that binds skin cells together. “A commonly used analogy for the interaction between your skin cells and their lipid barrier is that it’s like a brick wall—the skin cells are very much like the bricks, comprising the bulk of the physical structure; the lipids are essentially the mortar for the wall, holding the bricks together and supporting the overall integrity of the wall itself,” explains Ali Tobia, a licensed esthetician in New York City. “And much like a brick wall that begins to decay when its mortar cracks, your skin is much more prone to damage when its lipid barrier is not performing as well as possible.” This is where slugging provides its most effective benefit: By reinforcing the lipid barrier, it is artificially strengthening the way that your skin protects itself. “When the lipid barrier is weak, slugging does the work instead,” says Tobia. “Just like that brick wall, if you were to repair the mortar and get cracks and decay in the same spots again, eventually, you’ll want to find out what’s causing that and address it. But if you’re dealing with dryness or skin damage right now and want to give your moisture level a boost to try to rebalance your skin, slugging is a great reparative approach.”

How is skin slugging different from regular moisturizing?

Moisturizers hydrate your skin, while petroleum-based products are occlusives—meaning they lock in that hydration. “Occlusives are not breathable, which reduces transepidermal water loss,” says Michelle Henry, MD, a board-certified dermatologist and clinical instructor of dermatology at Weill Cornell Medical College in New York City. “This helps skin retain moisture better.” Conversely, while products like petroleum jelly lock in moisture, they don’t actually moisturize the skin. “They’re not interchangeable processes,” says Tobia. “Slugging doesn’t offer any moisturizing benefits of its own, but it can enhance the benefits of your already-effective moisturizer.”

What are the downsides of skin slugging?

This one should be obvious: Occlusive products may clog pores if you have oily or acne-prone skin. “While the products themselves are non-comedogenic, if any other products in your routine trigger acne, it will lock it in,” explains Dr. Henry. Additionally, Tobia warns against using active ingredients underneath an occlusive. “Slugging is going to lock in whatever product you put on before it, so you have to be careful about combining an occlusive layer on top of a particularly active ingredient, like retinoids, because that can often cause irritation,” says Tobia. “Also keep in mind that slugging has to be the last thing you do at the end of your routine. So if you forget a step in your regimen, you either have to skip it, or cleanse off the occlusive layer and start over, which is obviously not ideal.” Slugging is not a permanent solution but works better for those with short-term skin dryness or damage. “If you need a remedy beyond a few weeks of slugging a few nights per week, you probably need something that is more specifically targeted for whatever is causing your condition,” says Tobia.

How should you slug your face?

After your regular cleansing and moisturizing routine at night, take a pea-sized amount of petroleum and gently spread it onto your fingertips. Most dermatologists recommend using Vaseline Petroleum Jelly ($4; amazon.com), Aquaphor Healing Ointment ($15; amazon.com), or CeraVe Healing Ointment ($11; ulta.com). After lightly coating your fingertips, press firmly into your face, all over, to apply it to your skin. “This is where the brick-and-mortar analogy can also be helpful, because if you’re visualizing that brick wall, it’s easy to imagine yourself reinforcing the mortar of your skin’s lipid barrier,” says Tobia. To prevent your face from getting super greasy, apply only a very thin layer of ointment—Dr. Marchbein likes to dab a tiny bit on each cheek, forehead, nose, and chin, and then gently rub or pat in. “I would also try to sleep on your back and consider changing your pillowcase more frequently [when slugging],” says Dr. Marchbein. “If you don’t want to apply the ointment to your entire face or are acne-prone, you can use petroleum jelly to your lips and eyelids only. I always sleep with these to help hydrate the most delicate areas of the face.”