Mineral Oil

Overview

Mineral oil is a clear, almost water-thin to light-syrup-thin liquid distilled and refined from petroleum. Cosmetic-grade mineral oil (USP, BP, or Ph. Eur. certified) is exhaustively refined to remove polycyclic aromatic hydrocarbons, and decades of safety studies have established it as one of the most thoroughly evaluated cosmetic ingredients in use.

In INCI it is often listed as paraffinum liquidum (the European naming) or mineral oil (the American naming). On a label, both mean the same molecule.

You will see different viscosities sold for different applications:

• Light mineral oil (low viscosity) — used in baby oils, makeup removers, and bath oils
• Medium mineral oil — used in hair products and body oils
• Heavy mineral oil / liquid paraffin — used in salves, ointments, and lip balms

Shelf life is essentially indefinite. Mineral oil does not oxidise or feed microbes.

What it does in a formula

Mineral oil sits on the skin and forms a smooth, occlusive layer. It does not penetrate the stratum corneum — the molecule is too non-polar and too large to cross the barrier — which means it has two effects:

• Occlusive moisturiser — reduces transepidermal water loss by 30-50%, lower than petrolatum but meaningful
• Spreading and slip agent — lubricates skin and helps other ingredients spread evenly

It is one of the cleanest, most predictable emollients in the toolkit. No oxidation, no rancidity, no allergic reactions, no comedogenic activity (cosmetic-grade has been demonstrated repeatedly to be non-comedogenic in human studies despite older scares).

The marketing controversy is well-known: many “natural” brands have spent years messaging that mineral oil is somehow toxic or pore-clogging. The scientific evidence does not support those claims for cosmetic-grade material. The actual concerns — PAH contamination — apply only to non-cosmetic-grade petrolatum products, which are not sold for skincare use.

How to use

Add to the oil phase. Heat-stable up to 100 C and beyond.

Usage rates by product type:

• Baby oil: 100% (with optional fragrance)
• Bath oils: 30-90%
• Makeup removers: 30-90%
• Body oils: 20-80%
• Lip balms: 5-30%
• Body lotions: 3-15%
• Face creams: 2-8% (though “natural” positioning typically excludes this use)
• Hair conditioners and serums: 5-30%

It blends seamlessly with virtually every other oil-phase ingredient.

Best for / Worst for

Best for: baby and child oils (it is exceptionally well-tolerated), makeup removers, bath oils, eczema barrier products in clinical contexts, budget body lotions, hair-frizz oils, lip balms, anywhere you want a totally inert emollient.

Worst for: “natural” or “clean” brand positioning (the customer rejection is real regardless of evidence), formulations claiming organic certification (mineral oil is not certifiable as organic), products marketed to environmentally conscious customers (petroleum sourcing is the issue), formulations where you want active skincare benefit (mineral oil contributes none).

Common pitfalls

Believing or repeating the “mineral oil is dangerous” claims. Cosmetic-grade mineral oil has been studied as extensively as any cosmetic ingredient. The IARC, the EU’s SCCS, the US FDA, and Health Canada all classify cosmetic-grade mineral oil as safe. The “toxic” claims trace back to either confusion with non-cosmetic-grade industrial oils or misreading studies of PAH contamination in pre-1980s products.

Assuming it clogs pores. The 1970s rabbit ear comedogenicity studies do not translate to human skin. Modern human-based testing shows cosmetic-grade mineral oil is non-comedogenic. The “mineral oil clogs pores” claim is repeated in clean-beauty marketing without scientific support.

Underestimating customer perception. The science may say one thing, but customers in the natural-positioned market actively avoid mineral oil. If you make products for that audience, do not use it — not because it is unsafe, but because it will not sell.

Confusing different viscosities. Light mineral oil for baby products and heavy mineral oil for balms are not interchangeable for skin-feel.

Substitutes

• Squalane — plant-derived, similar light slip, more expensive, with the natural positioning win.
• Coco-caprylate — natural-derived, similar lightweight feel, better for the natural market.
• Caprylic/capric triglyceride — fully plant-based, similar light emollient role.
• Hemisqualane / hydrogenated polydecene — synthetic but non-petroleum, similar feel.
• Petrolatum — for balms and heavy occlusion (different texture, stronger occlusion).