In a beauty world that constantly cycles through trends, slugging has emerged as a technique with staying power, particularly for those battling dry, flaky skin. This Korean beauty practice has gained massive popularity on social media platforms, with users showcasing their petroleum jelly-slathered faces before bedtime. But beyond the viral videos and glowing testimonials lies actual science that explains why this seemingly simple technique can transform parched skin.
Slugging involves applying an occlusive agent typically petroleum jelly as the final step in your nighttime skincare routine. The name comes from the slug-like shine it leaves on your face, which might look odd but delivers impressive results by morning. While it might seem like just another beauty fad, the mechanism behind slugging is rooted in dermatological principles that have been understood for decades.
The Skin Barrier and Water Loss
Our skin’s outermost layer, the stratum corneum, functions as a protective barrier against environmental aggressors while simultaneously preventing excessive water loss from deeper skin layers. This barrier consists of dead skin cells (corneocytes) embedded in a matrix of lipids, forming a brick-and-mortar structure that keeps moisture in and irritants out.
When this barrier becomes compromised whether from harsh weather, aggressive cleansing, aging, or skin conditions like eczema trans-epidermal water loss (TEWL) increases. TEWL refers to the process by which water passes from inside the body through the epidermis and evaporates from the skin surface. Higher rates of TEWL lead to dryness, flakiness, irritation, and that tight, uncomfortable feeling many of us know too well during winter months.
This is where slugging comes in. By applying an occlusive agent like petroleum jelly, you create a physical seal over the skin surface. This barrier prevents water from escaping, essentially trapping moisture within the skin layers. Unlike moisturizers that add water or humectants that attract water, occlusives work by preventing the water already in your skin from evaporating.
A 2016 study published in the Journal of the American Academy of Dermatology found that petrolatum (the main ingredient in petroleum jelly) reduced TEWL by more than 98% when applied to skin. No other moisturizing ingredient has demonstrated this level of occlusive efficiency, which explains why petroleum jelly remains the gold standard for slugging.
The Science of Occlusion
The molecular structure of petroleum jelly makes it particularly effective as an occlusive agent. It consists of long hydrocarbon chains that form a semi-solid barrier on the skin surface. These molecules are too large to penetrate deeply into the skin, which means they remain on the surface where they can effectively prevent water loss.
Dr. Shereene Idriss, a board-certified dermatologist in New York City, explains: “Petroleum jelly creates a physical barrier that prevents 99% of water loss from the skin. This allows your natural skin repair mechanisms to work more efficiently overnight.”
The benefits extend beyond just preventing water loss. When skin is properly hydrated, it can better perform its natural regenerative processes. Cell turnover, the process by which new skin cells are formed and dead cells are shed, happens more efficiently in a hydrated environment. This leads to smoother, healthier-looking skin over time.
Additionally, slugging may help repair a damaged skin barrier. By preventing water loss and keeping the skin hydrated, it creates optimal conditions for the skin to repair itself. The lipids in the stratum corneum can reorganize and rebuild the barrier function when they’re not constantly battling dehydration.
A small study from 2022 published in the International Journal of Dermatology found that participants who used petroleum jelly on compromised skin (after mild chemical exfoliation) showed faster barrier recovery than those who used no occlusive. Their skin returned to normal hydration levels approximately 40% faster.
I tried slugging myself last winter when my face felt like sandpaper despite using expensive moisturizers. After three nights, the difference was noticeable my skin felt smoother and looked less red and irritated. The transformation wasn’t immediate, but it was significant enough that I’ve kept petroleum jelly in my skincare arsenal ever since.
Who Benefits Most from Slugging?
Slugging isn’t a one-size-fits-all technique. It works best for specific skin types and conditions:
Dry skin types benefit tremendously from slugging because they naturally produce less sebum (skin oil) and have a compromised moisture barrier. The occlusive effect helps supplement what their skin lacks naturally.
People with eczema or psoriasis often find relief through controlled slugging. Dr. Emma Guttman-Yassky, dermatology professor at Mount Sinai, has noted in her research that petroleum jelly can reduce flare-ups in eczema patients by maintaining skin barrier integrity.
Those in dry climates or during winter months may benefit from occasional slugging, as environmental factors can significantly increase TEWL.
Mature skin, which produces less natural oils and has a thinner barrier, often responds well to gentle slugging a few times per week.
However, slugging isn’t right for everyone. People with acne-prone or oily skin might find that the occlusive nature of petroleum jelly traps bacteria, sweat, and sebum against the skin, potentially worsening breakouts. The technique can also be problematic for those with fungal acne, as the occlusive environment might promote yeast growth.
My friend with combination skin tried slugging and woke up with tiny bumps across her T-zone. She modified the technique by applying petroleum jelly only to her dry cheeks and avoiding her oily areas completely, which worked much better for her specific needs.
Proper Slugging Technique
For slugging to work effectively without causing problems, proper application is key:
Start with clean skin. Double cleansing is recommended to remove all traces of makeup, sunscreen, and environmental pollutants.
Apply your regular skincare products, including treatments and moisturizers. Slugging works best when it seals in beneficial ingredients.
Take a pea-sized amount of petroleum jelly, warm it between your fingers, and apply a thin layer to your face. The layer should be thin enough that it doesn’t rub off on your pillow.
Slugging works best as an overnight treatment, allowing 6-8 hours for the skin to repair itself under occlusion.
In the morning, gently cleanse your face with a mild cleanser to remove the petroleum jelly residue.
For most skin types, slugging 2-3 times per week is sufficient. Daily slugging might be beneficial during extremely dry periods or for very dry skin types.
A common mistake is applying too much product. You don’t need to look like you’ve been dipped in grease a thin, barely visible layer is all that’s required for the occlusive effect to work.
Another important consideration is product selection. While Vaseline is the most well-known petroleum jelly brand, other options like Aquaphor and CeraVe Healing Ointment combine petroleum with additional beneficial ingredients like ceramides, glycerin, or panthenol. These formulations might offer extra benefits beyond simple occlusion, particularly for sensitive or compromised skin.
The concept of slugging isn’t limited to facial application. The same principles apply to extremely dry areas like elbows, knees, and feet. Many dermatologists recommend applying petroleum jelly to damp feet and wearing cotton socks overnight for dramatically softer feet by morning a technique sometimes called “foot slugging.”
Research continues to validate what many have discovered through practice. A 2020 review in the Journal of Dermatological Treatment examined various moisturizing strategies and found that products containing petrolatum consistently outperformed other moisturizers for barrier repair and hydration maintenance in compromised skin.
So while slugging might seem like just another social media beauty trend, its effectiveness is backed by solid dermatological science. For those with dry, dehydrated skin, this simple technique might be the missing piece in their skincare routine. Just remember that skincare is highly individual what works wonders for one person might not suit another. Pay attention to how your skin responds and adjust accordingly.
The beauty of slugging lies in its simplicity and accessibility. Unlike many trending skincare techniques that require expensive products or complicated routines, all you need is a jar of petroleum jelly one of the most affordable skincare products available. This democratic approach to skincare makes effective moisture barrier repair accessible to almost everyone, proving that sometimes the most effective solutions are also the simplest.