Slugging is a Korean skincare trend that entails slathering your skin with petrolatum or Vaseline to help improve the skin’s moisture content.
Slugging is works by trapping water underneath an occlusive layer or barrier forming ingredient, such as petrolatum. This barrier helps to prevent what’s known as transepidermal water loss or TEWL. TEWL occurs when the skin loses water to the air.
Transepidermal water loss occurs when the skin’s natural barrier is unable to function properly due to damage, as we age and produce less natural oils in our skin and if you are using harsh products such as some exfoliators, acids or retinols.
How To Slug?
Slugging is pretty simple, apply a small pea sized amount of vaseline or petroleum jelly over your skin before bed.
To enhance the benefits of slugging it is often useful to apply your normal skincare routine underneath the petroleum jelly to help trap in moisture. Ingredients such as hyaluronic acid and glycerin can be useful to boost the hydrating effects of slugging.
What Is The Skin Barrier?
The skin barrier refers to the top layers of skin, natural oils or sebum, ceramides, cholesterol and fatty acids. The barrier helps to protect the skin from bacteria, allergens and fungi as well as prevent water loss to the air. The balance of skin cells and natural oils are crucial for a healthy skin barrier. The oils or lipids act like glue between the skin cells, creating a barrier that protects your skin.
When the skin loses moisture or water to the air it is called transepidermal water loss. When the skin lacks moisture it can exacerbate fine lines, wrinkles, dull skin and can make the skin look dehydrated. Petrolatum forms a barrier that protects the skin, much like the skin’s natural barrier does.
When the skin’s natural barrier is disrupted or damaged it can cause irritation and sensitivity. The skin’s barrier can be damaged by overexfoliation, overuse of active skincare ingredient, genetics, and environment. Damage to the skin’s natural barrier has been linked to conditions such as eczema, dermatitis and psoriasis.
What Are The Benefits Of Slugging?
The main benefit of slugging is that it prevents water loss, leaving the skin hydrated and looking dewy. However, slugging may also help to improve the healthy functioning of the skin. Without adequate moisture the skin is unable to function properly. So, by increasing the moisture content of the skin, slugging may help to improve the skin’s health.
Using an occulsive ingredient such as petrolatim can help to reduce transepidermal water loss by upto 99%. While some transdermal water loss is important as it signals to the skin that more natural oils are needed, slugging may help to reduce this water loss and improve the appearance of the skin. Slugging is best to perform at night, partly to avoid looking like you have slathered on a shiny film all over your face, which you have and because it gives your skin the daytime to self-regulate.
Slugging helps to protect the skin from damage and may also help to support healing if damage to the skin barrier has occured.
What Is Petrolatum?
Petrolatum is commonly used as a moisturizer and barrier, protecting the skin from bacteria, allergens, and moisture loss. Petrolatum, also known as petroleum jelly or Vaseline, is a colorless or pale-yellow ointment. It is a mixture of hydrocarbons, which are compounds made up of hydrogen and carbon.
Petrolatum is thought to be occlusive, meaning that it creates a barrier on top of the skin, acting to protect the skin from transepidermal water loss or TEWL and preventing infection or irritation by bacteria or allergens.
What Is An Occulsive Ingredient?
Occulsive ingredients are ingredients that form a barrier on the surface of the skin. Some common occulsive ingredients include paraffin, mineral oil, squalane and petrolatum.
In terms of slugging, petrolatum is the main ingredient that is used as it is a readily accessible ingredient, inexpensive and forms a nice film on the surface of the skin.
Petrolatum functions as an occlusive agent and skin protectant. Petrolatum is an occlusive agent that reduces the rate of water loss through the skin to air and the environment.
Since petroleum has a melting point that is close to body temperature, it softens upon application and forms a water-repellent film around the applied area. This film prevents evaporation of the skin’s natural moisture and increases skin hydration by causing a build-up of water in the stratum corneum or the outermost layer of skin.
Furthermore, petrolatum has been shown to penetrate deeply into damaged skin and enhance the recovery of the skin’s barrier function. Maintaining a strong, intact barrier is essential to keep harmful things like allergens, bacteria, and irritants from entering the body through the skin.
When Should You Be Slugging?
Slugging is usually best to perform at night. This is because slugging relies on creating a film or barrier on the surface of the skin. This film can interact with makeup, disrupt sunscreen and leave the skin looking slick.
The benefit of slugging at night is that it provides the skin with protection and moisture loss at night. Moisture loss can occur more overnight as the skin comes into contact with the fabric of your pillowcase.
Is Petrolatum Safe?
One of the main issues that surrounds using petrolatum or Vaseline is misinformation that it is unsafe.
The clean beauty movement is somewhat to blame for these false rumours. These rumours claim that petrolatum is toxic due to contamination concerns and claims that the ingredient causes cancer. These rumours argue that petrolatum isn’t refined in the United States and as such doesn’t meet the purity standards required for safe use.
These claims are in stark contrast to all scientific evidence. Petrolatum is a highly refined ingredient that doesn’t contain any cancer-causing impurities. It is refined in the United States under the regulation of the US Food and Drug Administration and has been since the 1960s.
The impurity that is at the centre of these concerns is polycyclic aromatic hydrocarbons or PAHs. Some online blogs and reference sites argue that PAHs increase breast cancer risk by 50%.
The study that these sources refer to actually looked at the risks of PAH in relation to cigarette smoking and grilled or charred food which are other sources of PAH. The study didn’t look at the petrolatum and there is no substantive evidence to support the claim that petrolatum contains this impurity.
Slugging And Acne
Slugging can be useful for those with acne or acne-prone skin, however, it is not for everyone with breakouts.
Some acne types may benefit from slugging, particularly skin types that experience both acne and dryness. However, a good general rule for acne-prone skin is to avoid occulsive ingredients.
Slugging And Sensitive Skin
Slugging can be beneficial for sensitive skin types, particularly when the sensitivity is linked to damage or disruption of the skin barrier.
It is important to note that if you have sensitive skin that also produces heat, such as skin conditions like rosacea, the occulsive barrier can trap in heat and potentially worsen the condition.
Petrolatum isn’t itself irritating or likely to cause sensitivity, so if you are experiencing sensitivity when using petrolatum then it is likely to be another product or ingredient you are using.
Can You Slug Your Lips?
Absolutely. While you will probably be familiar with using Vaseline for your lips you may not know that using your serum and moisturizer underneath the Vaseline can help boost the hydration and reduce those chapped lips.
Similar to slugging on your skin, it is best to do at night, that way you aren’t losing the barrier to the rim of your coffee mug or to the sandwich you’re having for lunch.
Is Petrolatum Comedogenic?
Petrolatum itself is not comedogenic. This means that petrolatum doesn’t clog the pores or contribute to breakouts or pimples.
However, while petrolatum isn’t comedogenic, it can trap other ingredients close to the skin. For example, if another product you are using is comedogenic, petrolatum can push the other product deeper into the skin.
A similar effect can occur when you sweat or trap makeup under the occlusive barrier, increasing the likelihood of developing breakouts and pimples.
Hamishehkar H, Same S, Adibkia K, et al. A comparative histological study on the skin occlusion performance of a cream made of solid lipid nanoparticles and Vaseline. Res Pharm Sci. 2015;10(5):378-387.
Sethi A, Kaur T, Malhotra SK, Gambhir ML. Moisturizers: The Slippery Road. Indian J Dermatol. 2016;61(3):279-287.