Original Deo Stick

A lightweight, volatile silicone that gives serums and primers their silky slip and quick-evaporating finish. Human safety data are reassuring; the EU restriction on this ingredient in rinse-off products is about environmental persistence in waterways, not skin safety.

An aluminum salt used in antiperspirants to temporarily plug sweat ducts and reduce underarm wetness. Regulatory safety reviews have not found credible evidence linking its cosmetic use to breast cancer or Alzheimer disease.

A fatty alcohol derived from stearic acid that thickens creams and gives them a smooth, non-greasy glide. It is one of the fatty alcohols the CIR panel reviewed together and found safe as used, with a very low reported rate of contact sensitization.

A light synthetic emollient that gives creams a smooth, non-greasy slip, a common alternative to mineral oil in Korean formulas. It sits on the skin surface and is graded low concern in published assessments.

A thickening emulsifier derived from castor oil that has been saturated with hydrogen for stability. It helps form creams and lotions while conditioning the skin. CIR and EU assessments support its safety in cosmetics at typical use levels.

A mineral powder valued for its absorbent and soft-feel properties in cosmetics. Cosmetic-grade talc is required to be asbestos-free; inhalation risk from topical application is minimal. Generally well tolerated when used as intended.

An undisclosed scent blend that can contain dozens of components. The single most common cause of cosmetic contact allergy, and the blend is not itemized, so you cannot see what is in it.

A mineral thickener and anti-caking agent widely used in sunscreens and cosmetics to control texture and prevent ingredient separation. CIR has reviewed silica in cosmetic use and found no basis for concern at the levels used topically.

A more stable, esterified form of vitamin E used as an antioxidant and skin-conditioning ingredient. It is a different substance from the vitamin E acetate implicated in vaping-related lung injury, which involved inhaling the oil, not applying it topically to skin.

Alpha-isomethyl ionone is a violet-scented fragrance material and one of the EU-listed allergens requiring label disclosure. Documented sensitization is more common with this ingredient than with many other listed fragrance allergens.

A fragrance fixative and solvent found naturally in balsams and used to help scents last longer. It is one of the 26 EU-designated fragrance allergens, with documented but uncommon contact sensitization.

Benzyl cinnamate is a fragrance ingredient found naturally in balsams and is included on the EU disclosure list of potential allergens. Reported sensitization rates are low relative to other listed allergens.

A natural fragrance component found in citrus oils and lemongrass, giving a lemony scent. It is a named EU fragrance allergen that can oxidize into potent contact allergens over time; people with known fragrance sensitivities may react.

A rose-scented fragrance ingredient found naturally in geranium and rose oil. It is one of the 26 fragrance allergens the EU requires to be labeled by name because a minority of people develop skin sensitization to it, though most users tolerate it without issue.

A sweet, hay-like fragrance ingredient naturally found in tonka bean and lavender. It is one of the 26 EU-designated fragrance allergens and is also subject to an EU maximum concentration limit in finished cosmetic products.

A floral, rose-like fragrance compound found in many essential oils. It is one of the 26 EU-designated fragrance allergens, meaning a documented minority of people can develop contact sensitization, so brands must disclose it above set thresholds.

Hydroxycitronellal is a lily-of-the-valley scented fragrance ingredient on the EU allergen disclosure list. It has well-documented sensitizing potential in patch-test studies, so it is worth checking the label if you have known fragrance sensitivities.

A citrus-scented fragrance component. Fine for most, but it oxidizes over time into a known contact allergen, so it must be labelled in the EU.

A floral fragrance component and one of the EU-labelled fragrance allergens. Usually fine, worth watching if you react to scented products.