Ghost Oil

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.

Dimethiconol is a silicone emollient closely related to dimethicone, used to add slip and a smooth finish to creams and serums. It shares dimethicone's long-standing safety record and is considered non-sensitizing and non-comedogenic in typical use.

A silicone that gives a smooth, soft feel and helps hold water in the skin. Inert and well studied.

A light silicone emollient that spreads easily and gives a dry, non-greasy finish, common in Korean sunscreens and primers. It stays on the skin surface and is graded low concern in published assessments.

A silicone with phenyl groups that provides conditioning and a refined feel in foundations and color cosmetics. It is inert and well tolerated across skin types.

A fatty-acid and tocopherol-rich plant oil used as a hair and skin emollient; CIR's review of plant-derived fatty acid oils found no evidence of irritation or sensitization and a long history of safe use in food and cosmetics.

Green tea extract is a well-studied topical antioxidant with a long history of use in serums and moisturizers, generally well tolerated at cosmetic concentrations. Panel safety reviews of Camellia sinensis-derived ingredients have not identified meaningful topical hazard.

A glycerin derivative used as a skin conditioner and preservative booster, often paired with phenoxyethanol to allow lower total preservative levels. It has a low irritation and sensitization profile in safety reviews.

A humectant that draws water into the skin. One of the best-studied, best-tolerated ingredients in personal care.

A crosslinked silicone polymer that creates a velvety texture in primers and powders. The crosslinked structure does not change its safety profile, and it is inert and well tolerated.

A silicone-based UV filter that provides broad-spectrum protection. Approved in cosmetics and graded safe; the silicone backbone makes it stable and non-irritating.

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 widely used preservative, safe at the legal limit of 1% or less. Often the "paraben-free" replacement.

A chelating agent that binds trace metal ions to keep formulas stable and preservatives working properly. It is not a functional skincare "active" and only a very small amount is used, with minimal skin penetration expected.

A widely used, gentle preservative also common in food. It is generally well tolerated, though it can occasionally cause mild, transient irritation in people with already-compromised or very reactive 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.

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.

Benzyl salicylate is a fragrance fixative that also absorbs some UV light. It is on the EU allergen disclosure list, but the evidence suggests it sensitizes fewer people than most other listed fragrance allergens.

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 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, 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.

A jasmine-like fragrance compound frequently used in soaps and lotions. It is one of the 26 EU-designated fragrance allergens, though studies suggest its sensitization potency is comparatively low relative to other listed allergens.

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