What's actually in a tube of petroleum jelly.

Most people have used petroleum jelly their whole lives without knowing what it is. The brand name is famous. The container is universal. The texture is unmistakable. But ask anyone what petroleum jelly actually is and you'll usually get "some kind of oil" and a shrug.

It's worth knowing. Not because it's secretly dangerous (it isn't, in its refined form), but because once you understand what's in the jar, the conversation about what to use instead makes a lot more sense.

Where it comes from

Petroleum jelly is a byproduct of crude oil refining. When crude oil is fractionally distilled to produce petrol, diesel, jet fuel, and lubricants, one of the residues left behind is a waxy substance called slack wax. Slack wax is then deoiled, hydrogenated or acid-treated, and filtered through activated carbon and clays to remove impurities. What's left is a semi-solid mixture of saturated hydrocarbons in the C16 to C32 molecular weight range. That's petrolatum.

It was discovered in 1859 by oil rig workers who noticed a waxy gunk that built up on drilling equipment. They were already rubbing it on minor burns and scrapes before anyone had any idea why it worked. By 1872 it had been refined into a consumer product and trademarked. The brand name became so dominant that most people now use it as a generic term, the same way they say "hoover" for vacuum cleaner.

Not all petroleum jelly is the same

This is the bit most consumers don't know. The petrolatum in your medicine cabinet is heavily refined. The petrolatum used in industrial lubricants and packaging is not. The difference matters.

Refined cosmetic and pharmaceutical-grade petrolatum (often labelled USP-grade or Ph.Eur-grade) goes through aggressive purification to remove polycyclic aromatic hydrocarbons (PAHs), which are a class of compounds linked to cancer in their unrefined state. Once stripped out, what's left is chemically inert, low-allergenic, and clinically validated as a skin protectant.

Unrefined petrolatum still contains those PAHs. It's not what's in your moisturiser, but it's worth understanding the spectrum. The European Union takes this seriously enough that petrolatum sits on its CMR list (substances classified as carcinogenic, mutagenic, or reprotoxic), with refined grades that pass specific PAH tests exempted from the restriction. The exemption is real, the listing is also real, and both reflect the fact that petrolatum is a category, not a single substance.

Penreco. Petrolatum and Regulatory Requirements. Industry technical brief on USP-grade exemption from EU CMR list.

U.S. Pharmacopeia. Petrolatum, USP. Monograph specification for pharmaceutical-grade purity.

What it actually does on skin

Refined petrolatum is one of the most effective occlusive agents available. It reduces transepidermal water loss by approximately 98%, which is the benchmark every other barrier product is measured against. It's an FDA Category I OTC skin protectant, meaning it has regulatory drug-status approval for chapped skin, minor cuts, scrapes, and burns. It's stable, non-comedogenic at standard concentrations, and rarely causes contact reactions because the molecules are too large to penetrate the stratum corneum.

That's the case for petrolatum. It's a real one.

What petroleum jelly doesn't do

It doesn't suffocate skin. The myth that petrolatum prevents oxygen exchange is wrong, the molecular structure is permeable to oxygen and water vapour, just not liquid water. It doesn't add anything to skin. It's chemically inert. There are no vitamins, antioxidants, fatty acids, or active compounds in a tube of petroleum jelly. The skin doesn't recognise it, integrate it, or use it for anything. It just sits there, blocks water from leaving, and waits to be wiped or washed off.

That last point is the one that matters.

Why it's the wrong daily-wear tool

Inertness is petrolatum's strength for acute use and its limitation for everyday skincare. If your skin is bleeding, post-procedure, or actively raw, you want something that does nothing except seal. Petrolatum is exactly that. The skin underneath does its own work and the petrolatum holds the line until the work is done.

If your skin is just under daily pressure (washing, weather, friction, age) you want something that does more than hold the line. You want lipids the skin can integrate into its own barrier matrix, which is the structural problem inert occlusion can't solve. You can keep petrolatum-sealing depleted skin for years and the underlying barrier never rebuilds, because there's nothing in the jar that contributes structurally to the rebuild.

This isn't a moral position about crude oil. It's a chemistry one about what the skin can and can't do with what you put on it.

What changes when you use lipid-based balms instead

Plant-derived lipids and skin-identical fatty acids work differently from petrolatum. Squalane is nearly identical to squalene, a natural component of human sebum. Jojoba oil is a wax ester structurally similar to the wax esters already present in your stratum corneum. Shea butter is rich in linoleic acid, which is a precursor to ceramides, the dominant lipid in your barrier matrix. The skin recognises these compounds and uses them. Instead of just blocking water from leaving, the formula contributes to the structure that keeps water in by design. We've written a full piece on this if you want the side-by-side comparison: Petroleum jelly versus plant lipids: what your skin actually does with each.

The trade-off is that lipid-based balms reduce TEWL less aggressively than petrolatum. Approximately 50 to 70% reduction depending on the formula, versus petrolatum's 98%. For acute, raw, post-procedure skin, that gap matters and petrolatum wins. For daily wear on healthy-but-stressed skin, the gap doesn't matter and the structural contribution wins.

Lin TK, et al. Anti-inflammatory and skin barrier repair effects of topical plant oils. Int J Mol Sci. 2017;19(1):70.

Pazyar N, et al. Jojoba in dermatology: a succinct review. G Ital Dermatol Venereol. 2013;148(6):687-691.

What to look for on a label

If you're switching away from petroleum jelly for daily wear, the labels can be confusing. Here's what to read past the marketing:

Petroleum-based ingredients to recognise

Petrolatum, mineral oil, paraffinum liquidum, paraffin wax, microcrystalline wax, ceresin, ozokerite. All of these are crude-oil-derived. None are plant-based, even when they appear in products marketed as natural.

Plant-based lipid ingredients worth recognising

Squalane (olive-derived), jojoba oil (Simmondsia chinensis seed oil), shea butter (Butyrospermum parkii), cocoa butter (Theobroma cacao), MCT oil or caprylic/capric triglyceride (coconut-derived), beeswax (cera alba). These are the structural lipids that integrate into the skin's own barrier.

Watch the order of ingredients

In any cosmetic formula, ingredients are listed in descending order by concentration. If "petrolatum" or "mineral oil" is first or second on the list of a product marketed as natural, the marketing is doing more work than the formula.

What NOOKS Everywhere Balm™ uses instead

Anhydrous, 15 ingredients, no petroleum, no mineral oil, no synthetic occlusives. MCT oil, jojoba, squalane, and shea butter as the structural lipids. Calendula, plantain leaf, helichrysum, and bisabolol as the recovery botanicals. Bakuchiol as a retinol-adjacent active. Beeswax as the structural binder. The formula was developed across three iterations and user-tested on intimate skin with zero reported reactions. Full ingredient breakdown is here.

The honest summary

Refined petroleum jelly isn't dangerous. It's just inert. For acute use it earns its place. For daily wear, on skin that's just under everyday pressure, you can do better than something that does nothing but block.

Balm without the petrol. Actives without the sting. No off limits.

$29.95. One tin. Wherever skin is asking for more than a seal. Shop NOOKS Everywhere Balm™.