Petrolatum, the waxy substance in products like Vaseline, is not inherently bad for your skin or health when it meets pharmaceutical-grade purity standards. The concerns you’ve likely encountered online center on two issues: its petroleum origins and the possibility of contamination with cancer-linked compounds. Both deserve a closer look, because the full picture is more nuanced than most sources suggest.
The Contamination Concern
Petrolatum is derived from crude oil, which naturally contains polycyclic aromatic hydrocarbons (PAHs), a group of compounds linked to cancer. This is the primary reason petrolatum has a bad reputation. If the refining process is incomplete, trace amounts of these compounds can remain in the final product.
Industrial-grade petrolatum, used in manufacturing and machinery, does carry higher levels of PAHs because it’s held to less stringent purity standards. This is the type that genuinely raises health concerns, and it’s not what you’ll find in your medicine cabinet. The petrolatum sold in skincare products, cosmetics, and over-the-counter ointments in the U.S. and Canada is almost always USP (United States Pharmacopeia) grade, which must pass specific ultraviolet absorbance tests designed to detect residual PAHs. Modern refining techniques like solvent extraction and deep hydrotreating virtually eliminate 3- to 7-ring PAHs from USP petrolatum.
The Canadian government conducted a formal screening assessment of petrolatum and waxes, calculating a theoretical cancer risk from any PAHs that might remain in refined consumer products. The assessment confirmed a low potential for risk. The European Union takes a stricter approach, requiring that petrolatum in cosmetics show a full refining history proving the starting material is not carcinogenic. This doesn’t mean EU regulators consider refined petrolatum dangerous; it means they want documented proof of adequate processing.
Does Petrolatum Clog Pores?
This is one of the most persistent claims against petrolatum, and it’s largely a myth. Pure petrolatum (100% USP grade) is not listed on standard comedogenicity scales and is classified as non-comedogenic. It sits on the surface of your skin rather than penetrating into pores. It feels greasy, which is probably why so many people assume it causes breakouts, but the texture and the effect on pores are separate things.
That said, petrolatum does form a thick occlusive layer. If your skin is already dirty or if a product combines petrolatum with other comedogenic ingredients, you could experience clogged pores. The petrolatum itself isn’t the culprit, but trapping dirt, bacteria, or pore-clogging additives underneath it can contribute to problems. Applying it to clean skin avoids this issue.
How Petrolatum Actually Works on Skin
A common criticism is that petrolatum “does nothing” for skin because it’s inert, just sitting on top like a plastic wrap. Research published in the Journal of Allergy and Clinical Immunology tells a different story. When applied to skin, petrolatum triggered the expression of filaggrin and loricrin, two proteins essential for building a healthy skin barrier. It increased the thickness of the outermost skin layer and significantly reduced immune cell activity in skin affected by eczema, even in patches that appeared normal.
So petrolatum isn’t simply a passive shield. It actively supports skin repair by creating conditions that allow the skin’s own biology to recover. This is why dermatologists frequently recommend it for eczema, wound healing, and cracked skin. It remains one of the most effective occlusive moisturizers available, reducing water loss from the skin by up to 99% in some measurements.
Allergic Reactions Are Extremely Rare
Another concern is that petrolatum might cause allergic reactions. An analysis of nearly 80,000 patients patch-tested with pure white petrolatum between 1992 and 2004 found that only 0.03% had a positive allergic reaction. Just 2 patients out of the entire group had a strong positive reaction. The vast majority of non-negative results (0.3%) were classified as doubtful or mildly irritant rather than truly allergic. The researchers concluded that white petrolatum is essentially a non-sensitizer, and the handful of reactions likely reflected individual susceptibility rather than a property of petrolatum itself.
For context, common skincare ingredients like fragrances and preservatives trigger allergic reactions at far higher rates. Petrolatum is so well tolerated that it’s actually used as the base vehicle in patch testing itself, the standard method allergists use to identify skin allergies.
When Petrolatum Could Be a Problem
The legitimate concerns about petrolatum are narrow but worth knowing. Products sourced from countries with weaker refining regulations, or products that don’t specify USP or pharmaceutical-grade petrolatum, could theoretically contain higher levels of PAHs. Discount or no-name brands that lack clear labeling deserve more scrutiny than established products that comply with FDA or EU standards.
Petrolatum can also trap heat and moisture against wounds in ways that aren’t always desirable. On burns or heavily infected skin, the occlusive barrier that makes petrolatum so effective for dry skin can sometimes slow healing or encourage bacterial growth. For deep or serious wounds, following specific wound care guidance matters more than defaulting to petrolatum.
Environmental and ethical objections are separate from health concerns. Petrolatum is a byproduct of oil refining, so people who avoid petroleum-derived products for ecological reasons may choose plant-based alternatives like shea butter or beeswax. These alternatives can be effective moisturizers, though none match petrolatum’s water-loss prevention at the same price point.
What to Look for on Labels
If you want to use petrolatum safely, check for “white petrolatum USP” or “petrolatum USP” on the ingredient list. This designation means the product has met pharmaceutical purity standards, including limits on PAH content verified through ultraviolet absorbance testing. Products labeled simply “petrolatum” without the USP designation, particularly in industrial or non-cosmetic contexts, may not have undergone the same level of refining. Major drugstore brands like Vaseline, Aquaphor, and CeraVe healing ointment all use USP-grade petrolatum.