Petrolatum, commonly sold as petroleum jelly or Vaseline, is used primarily to lock moisture into skin, protect wounds, and treat dry skin conditions like eczema. At a concentration of just 5%, it reduces water loss from the skin by more than 98%, making it the single most effective occlusive moisturizer available. Its uses span wound care, skin barrier repair, lip protection, and cosmetic moisturizing.
How Petrolatum Works on Skin
Your skin constantly loses water through evaporation, a process called transepidermal water loss. Petrolatum works by forming a physical barrier on the skin’s surface that traps that water before it escapes. It has a water vapor loss resistance 170 times greater than olive oil. For comparison, other common moisturizing ingredients like mineral oil and silicones only reduce water loss by 20 to 30%.
This barrier doesn’t just keep moisture in. It also keeps irritants, allergens, and bacteria out, giving damaged skin a protected environment to repair itself. The trapped hydration plumps up the outer layer of skin, making it thicker, more pliable, and more elastic.
Wound Care and Post-Surgical Healing
One of petrolatum’s most important uses is wound care. The American Academy of Dermatology recommends plain petroleum jelly as the go-to treatment for skin biopsy sites, and specifically advises against using antibiotic ointments. The reasoning: the risk of developing an allergic reaction to antibiotic ointment is higher than the risk of infection after a biopsy. Keeping the wound moist with petroleum jelly speeds healing.
Clinical research backs this up. A study comparing petrolatum-based ointment to a combination antibiotic ointment on surgical wounds found no difference in healing between the two for redness, swelling, crusting, or skin regrowth at any point during recovery. The antibiotic group actually reported more burning at the one-week mark, and one patient developed allergic contact dermatitis from the antibiotic. The petrolatum group had no such reactions.
If you have stitches, the AAD recommends applying petroleum jelly from a squeeze tube (not a jar, to avoid transferring germs) and keeping the wound covered until your doctor removes the stitches. A moist wound consistently heals faster than a dry one.
Eczema and Dry Skin Conditions
The National Eczema Association considers petroleum jelly a first-line treatment for mild to moderate eczema symptoms. Its effectiveness comes down to that powerful occlusive barrier: it prevents the moisture loss that triggers the dry, cracked, itchy skin characteristic of eczema flares.
A 2017 study found that daily full-body application of a moisturizer like petroleum jelly helped prevent eczema flare-ups. Among the seven moisturizers tested, petroleum jelly was also the most cost-effective option, which matters for a condition that requires consistent, long-term management. For people with eczema, regular use of petrolatum can reduce the frequency and severity of flares, potentially lowering the need for prescription treatments.
Lip Protection and Barrier Repair
Petrolatum is a staple ingredient in lip balms for good reason. The skin on your lips is thinner than the rest of your face and lacks oil glands, making it especially vulnerable to drying out. Research comparing pure petrolatum to fancier formulations containing “skin-identical lipids” found no advantage to the more complex product. Pure petrolatum performed just as well at restoring the skin barrier on damaged skin. For chapped or peeling lips, a thin layer of petroleum jelly is as effective as most specialty balms.
Slugging: The Overnight Moisture Technique
Slugging is a skincare trend that involves applying a thin layer of petroleum jelly over your entire face as the last step in your nighttime routine. The name comes from the shiny, slug-like appearance it creates. Dermatologists at the Cleveland Clinic confirm that it works well for people with dry, dehydrated, or compromised skin barriers. Overnight, the petrolatum layer prevents water loss and allows the skin underneath to repair itself.
Slugging isn’t for everyone, though. If you have oily or acne-prone skin, the extra occlusive layer can trap excess oil and make breakouts worse. You should also skip it over any active skin infection, since sealing bacteria under a barrier can prevent the infection from clearing. One important caution: avoid applying petrolatum over products containing alpha hydroxy acids, beta hydroxy acids, or retinoids. The occlusive seal traps these active ingredients against the skin, intensifying irritation.
Does Petrolatum Clog Pores?
The belief that petroleum jelly clogs pores is widespread but poorly supported. A comprehensive review published in the Journal of the American Academy of Dermatology found that several studies claiming petrolatum is comedogenic provided no references to back the claim. The one study that did report mild comedogenicity involved continuously applying petrolatum under occlusion (sealed bandaging) for six weeks, which is not how anyone uses it in real life. The same researchers later found that petrolatum actually improved acne papules in a subsequent study. The review’s conclusion: petrolatum is noncomedogenic for normal use.
Safety and Purity Standards
Unrefined petroleum products can contain polycyclic aromatic hydrocarbons, which are carcinogenic compounds. This is where product grade matters. USP-grade white petrolatum, the type sold for skin care and medical use in the United States, must meet strict purification standards set by the United States Pharmacopeia, including specific testing for these harmful compounds. The USP updated its standards to include UV absorbance limits specifically designed to detect polycyclic aromatic hydrocarbons in the final product. Any petrolatum you buy at a pharmacy or drugstore for skin use meets these standards.
Allergic reactions to petrolatum itself are extremely rare. While white petrolatum is used as the base substance in patch testing for contact allergies (because it’s considered essentially inert), a small number of people do react to it. In the most recent North American Contact Dermatitis Group testing data, nickel remained the most common allergen, and petrolatum reactions, while tracked, are uncommon enough that dermatologists still consider it one of the safest topical products available.
Common Everyday Uses
Beyond the clinical applications, petrolatum serves a range of practical purposes:
- Preventing chafing: Runners and athletes apply it to thighs, feet, and underarms to reduce friction during prolonged activity.
- Protecting skin from wind and cold: A thin layer on exposed skin acts as a physical shield against harsh weather.
- Locking in moisture after bathing: Applying petrolatum to damp skin within a few minutes of showering seals in the water your skin just absorbed.
- Softening rough patches: Heels, elbows, and knuckles respond well to overnight petrolatum application, especially under cotton socks or gloves.
- Diaper rash prevention: The moisture barrier protects infant skin from prolonged contact with wetness.
Petrolatum’s discovery traces back to 1859, when chemist Robert Chesebrough visited an oil well in Titusville, Pennsylvania, and noticed workers rubbing a thick, black residue from the drilling rigs onto their cuts and burns. He spent 11 years refining that substance in his Brooklyn laboratory before marketing it as “Wonder Jelly.” By 1874, he had registered the name Vaseline, combining the German word for water (wasser) and the Greek word for oil (elaion). More than 160 years later, the refined version of that same substance remains one of the most versatile and evidence-backed skin protectants available.