This viral TikTok trend was probably a part of your grandma's skincare routine

“If you’re 26-plus and you’re not slugging around your eyes, you need to be,” says TikToker @autumnelizafaith before jumping into an explanation of how to attempt one of the platform’s most notorious skincare hacks. In the video, the beauty influencer then takes a dollop of CeraVe Healing Ointment and rubs it around her eyes. “And then you go to sleep,” she says. If you explore one of the endless slugging hashtags, you’ll find that this ointment is just one of the top 5 gooey, translucent products that young people are slathering onto their faces before bed in the hopes of waking up with glowing skin.

“TikTok has the unique ability to transform niche beauty ‘hacks’ into viral crazes due to its fun, short-form videos, casual creativity, and most importantly, because of Gen-Z’s voracious appetite for the next, newest thing,” says Mallory Huron, beauty and wellness strategist at trend forecaster Fashion Snoops. “Gen-Z loves to experiment and participate in trend cycles, and don’t want to be left out of buzzy challenges.”

TikTokers like skincarebyHyram, Charlotte Paler, Jamie.Derm.Pa, have dropped detailed videos breaking down the slugging trend, but there are experts on the app too; Huron says dermatologists have been especially helpful in explaining the purpose and origins of slugging. Still, for the most objective take on whether this technique does anything at all for our skin, we reached out to experts who aren’t slugging on the app.

What is slugging?

Slugging is a skincare trend where a thick layer of Vaseline petroleum jelly (or the like) is applied to the full face before bed to lock in moisture. Many TikTok "hacks," as you can imagine, are total BS touted by uninformed influencers. But this one might have some validity.

“Petroleum jelly contains triple purified petrolatum, which is safe and effective as a skin protectant,” says New York-based dermatologist Joshua Zeichner, adding that slugging can be especially useful if you have dry skin. Contrary to popular belief, he says, vaseline should not actually clog your pores and cause pimples. However, it may leave your skin feeling heavy, especially if you have naturally oily skin.

Vaseline — the most popular slugging product — can also be applied over other active ingredients to help enhance penetration. “However, I do not recommend applying it over potentially irritating ingredients like retinol or hydroxyacids acids as this may lead to excess irritation,” says Zeichner. And when it comes to slugging, more is not better. Using small amounts rub fully into the skin is all you need.

How does it work?

For those whose skin does respond to slugging, sleeping with an emollient on your face can hydrate the skin and even improve the skin’s barrier. When your skin barrier is in tact, your skin is less likely to become red, inflamed, and flaky, says Sheila Farhang, a Tucson-based dermatologist and cosmetic surgeon.

“The skin is continuously repairing itself,” says New York-based plastic surgeon Ben Lee, who’s attuned to facial trends and aesthetics. “Old skin is shed constantly as it is replaced by new skin.” In other words, our skin is continuously trying to heal. And since a moist environment is optimal for wound healing, maximizing the moisture content of the skin gives it the best possible environment for self-repair, Lee says.

Okay, but is slugging actually necessary? No, it definitely isn’t, confirm my experts. Looks, our skin differs based on several factors, including genetics and the environment conditions of where you live. If you live in a low-humidity climate, Lee says, slugging may help you look less weathered. Helping our skin retain moisture could slow down the appearance of aging too.

People on TikTok use all kinds of products to slug. Huron says the key is to use something occlusive, meaning something that it forms a protective barrier to prevent your skin from losing moisture. But if you’re layering your slugging over the rest of your skincare routine, she explains, use moisturizers rich in hyaluronic acid or ceramides to ensure your skin is getting flooded with hydrating goodness.

“The theory behind slugging is that since it prevents moisture loss, it can ‘lock in’ the hydration and activate the products beneath so that they really sink into the deeper layers of the skin,” Huron says. Petroleum jelly is occlusive, which means it essentially stops water from evaporating and your skin from losing moisture overnight.

Where did the concept of slugging it come from?

The term “slugging” is new, but the idea and practice is definitely not. “Before there were modern moisturizers, our Taiwanese grandmothers had to get by with petroleum jelly and even animal grease applied to the face before going to bed at night,” says Lee. “The epidermis, or outer layer of the skin, functions as a barrier to external threats such as bacteria and other pathogens.”

Moisturizers — even the lighter ones — help our skin stay healthy by aiding in water retention. “Before they were available, dermatologists recommended heavier, more occlusive compounds for skin health. The ultimate and heaviest of these was Vaseline, which is pretty much the ultimate in mechanical skin protection.” In essence, we have rediscovered the most effective beauty skin treatment of yesteryear.

The recent wave of the trend, though, hails from South Korea. “It’s no surprise that slugging originated in [South] Korea, where skincare routines are king and skincare trends cycle at a lighting pace,” says Huron. There, dewy and plump skin is considered trendy, which Huron says very much explains the popularity of slugging. “Once the trend caught on in Korea, it made its way via social media buzz to TikTok, where it exploded.”

Why is this happening?

“Modern society worships youth,” says Lee. “With the explosion of social media, there is more pressure to look appealing than ever before in human history. It is no wonder that people are looking for any advantage they can get.” Ironically, it’s people who are actually young who are pushing the trend forward on TikTok

To put it simply, slugging is simple, affordable and moisturizes the skin, says Farhang. What makes it so appealing is the instant gratification it yields. “Vaseline is great at doing its job, and especially if you layer a hydrating, water-based moisturizer underneath it, you will in all likelihood wake up with very soft, dewy skin the first morning after slugging,” she says. This is, of course, unless you are very breakout-prone. It can also be a great way to quench seasonally dry skin, or to boost your glow before a big event.

There’s also a bit of ancient wisdom to it. “I anecdotally know of many older ladies who swear by putting Vaseline on their face every night before bed. Marilyn Monroe was known to do it as well,” says Huron. She thinks consumers are really fed up with complicated, pricey skincare routines that don’t yield results, and as such are very receptive to trends that promise unbelievable results with a basic drugstore product.

Can I slug other parts of my body?

Farhang says slugging for the body is worth trying. “I totally recommend it for the knees and ankles.” Which is exactly how it’s spreading on TikTok. “We’re already seeing ‘mini slugging’ popping up on TikTok, which refers to only applying petroleum jelly over smaller, more delicate areas of the skin, like the eyes and lips,” says Huron. This represents a more sensible and versatile take on the trend, as most people tend to be drier in these areas anyway, and using a Vaseline-like product to seal in an eye cream or a lip balm before going to bed could help to prevent overnight moisture loss. She’s done it herself and found it helpful in the winter.

Though Huron says consumers should really do their research before experimenting with a trend like slugging. “It’s really easy to be drawn into the appeal of a skincare trend as presented by social media, but it’s important to do patch tests and really look into something before giving it a go.” TikTok is a great place for experimentation and skincare exploration: While trends like slugging are mostly harmless, there are other trends that can be dangerous. “Do your research and have the patience to test these DIY hacks out slowly to avoid regret.”