Vaseline, or petroleum jelly, is not bad for you when used on the skin as directed. It has been used safely for over a century, and refined, pharmaceutical-grade petrolatum contains negligible levels of harmful contaminants. That said, there are a few specific situations where petroleum jelly can cause problems, and those are worth understanding.
Why People Worry About Petroleum Jelly
The concern usually comes down to one thing: petroleum jelly is derived from crude oil, and crude oil contains polycyclic aromatic hydrocarbons (PAHs), which are known carcinogens. That sounds alarming, but the refining process strips these compounds out almost entirely. PAH concentrations in finished petrolatum are negligible. The European Union restricts PAH content to less than 0.005%, and the U.S. Pharmacopeia now includes a specific UV absorbance test designed to detect these carcinogens in pharmaceutical-grade petrolatum.
Allergic reactions to petroleum jelly are extremely rare, which itself is evidence of how thoroughly the purification process removes potential irritants. When researchers have investigated the handful of reported allergic contact reactions, residual PAH traces were the suspected culprit. But these cases are so uncommon that petrolatum is actually used as the base for allergy patch testing, precisely because it almost never causes a reaction on its own.
How It Actually Helps Your Skin
Petroleum jelly is one of the most effective moisturizers available, not because it adds moisture to your skin but because it prevents moisture from escaping. It reduces water loss through the skin by about 98%, far outperforming other oil-based moisturizers, which typically reduce water loss by only 20% to 30%.
It works by forming a physical barrier on the skin’s surface. That barrier does two things: it traps water in the outer layer of skin, and it blocks irritating substances from getting in. The retained hydration plumps the outer skin layer like a sponge, making it thicker, more pliable, and more elastic. This is the principle behind “slugging,” a skincare trend where a thick layer of petroleum jelly is applied to the face overnight. It sounds greasy, but for people with dry or damaged skin barriers, it can be genuinely restorative.
Wound Care: As Good as Antibiotic Ointment
One of the more practical things to know about petroleum jelly is that it works nearly as well as antibiotic ointment for minor wound care. In a randomized trial of over 900 patients who had dermatologic surgery, infection rates were 3.6% for wounds treated with plain petrolatum and 2.7% for those treated with bacitracin (a common over-the-counter antibiotic ointment). That small difference wasn’t clinically meaningful, and plain petroleum jelly doesn’t carry the risk of allergic reactions that antibiotic ointments do.
Keeping a wound moist with petroleum jelly prevents scabbing and helps the skin heal more evenly. Many dermatologists now recommend it as a first-line option for post-surgical wound care.
The One Place to Be Careful: Inside Your Nose
The most legitimate safety concern with petroleum jelly involves using it inside the nostrils over a long period of time. When applied inside the nose, small amounts can slowly migrate down the back of the throat and, rarely, tiny quantities slip into the windpipe and lungs. Over months of regular use, this buildup can cause a condition called lipoid pneumonia, an inflammation of the lungs triggered by fat-based substances.
Lipoid pneumonia from nasal petroleum jelly use is uncommon, but it’s a real phenomenon with documented cases. Some people have no symptoms at all, while others develop a cough, chest pain, or shortness of breath. It typically shows up on a chest X-ray or CT scan. The treatment is straightforward: stop using the jelly, and the condition generally resolves, sometimes with a short course of anti-inflammatory medication.
If you’re using petroleum jelly for a dry nose occasionally, the risk is minimal. The concern is with daily, long-term use inside the nostrils, particularly in people who are already prone to aspiration (like older adults or those with swallowing difficulties). Saline sprays or water-based nasal gels are safer alternatives for chronic nasal dryness.
Who Should Avoid It on Skin
Petroleum jelly is non-comedogenic in the technical sense, meaning it doesn’t penetrate pores and trigger acne the way some oils do. But because it sits on the skin’s surface and traps everything underneath it, applying it over dirty skin or active breakouts can worsen acne by sealing in bacteria and sebum. If you’re acne-prone, using it on your face requires clean skin underneath.
People with very oily skin may find it uncomfortable or unnecessary, since their skin already produces enough natural oils to maintain a moisture barrier. And while true allergic reactions are exceptionally rare, they’re not impossible. If you notice redness or irritation after applying petroleum jelly to a small test area, discontinue use.
Purity Matters: Not All Products Are Equal
The safety profile described above applies to refined, pharmaceutical-grade petroleum jelly, the kind sold under brands like Vaseline or labeled as “USP grade” or “white petrolatum.” These products go through extensive purification that removes PAHs and other impurities. Industrial-grade petrolatum, or unrefined petroleum byproducts sold outside of regulated cosmetic and pharmaceutical channels, do not meet the same standards and could contain meaningful levels of contaminants.
Stick with well-known brands or products that specify USP-grade petrolatum, and the carcinogen concern effectively disappears.