Pure Wonder

The base most products are built on. It carries the other ingredients and has no safety concern.

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

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

A fatty alcohol used to soften skin and stabilize creams. Despite the name, it does not dry the skin.

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 solvent and emollient ester used in leave-on and rinse-off formulas. The CIR Expert Panel reviewed alkyl benzoates and found no irritation even at full strength, with typical use levels ranging from 0.0008 to 50 percent depending on product type.

A rich plant butter pressed from shea tree nuts, valued for softening and cushioning dry skin. It is generally well tolerated, though very rare allergic reactions have been reported and people with tree nut allergies who are cautious may want to patch test first.

A rich, solid-at-room-temperature oil that deeply softens dry skin and hair. It is well tolerated overall, but its high lauric acid content is considered comedogenic by many dermatologists, so it can trigger breakouts in people who are acne-prone.

A PEG-type emulsifier (ethoxylated cetearyl alcohol) that helps blend the water and oil parts of a cream. CIR concluded ceteareth ingredients are safe as used, with the one caveat that they are not meant for broken or damaged skin.

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

A lightweight hydrocarbon that gives formulas a smooth, silky feel. Used in color cosmetics and sunscreens. Well tolerated and inert.

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 saturated fatty acid found in palm oil and naturally in the skin, used as an emollient to soften and condition skin. It is one of the most studied fatty acids and is well tolerated.

A common emulsifier and texture-softener made from glycerin and stearic acid. CIR review of this class found no evidence of reproductive, carcinogenic, sensitizing, or phototoxic effects in the studies examined.

A naturally occurring fatty acid (also made in the body and found in many foods) used to thicken lotions and help stabilize cleansing bars. It is one of the most well-studied emollient ingredients and is not a meaningful irritant at cosmetic use levels.

Chlorphenesin is a preservative subject to an EU maximum concentration limit and has been linked to contact dermatitis in a minority of users, particularly with repeated exposure. Most people tolerate it at the regulated use level without issue.

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 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.

Carbomer is a synthetic polymer used purely to thicken and stabilize gels and lotions, with negligible skin penetration due to its large molecular size. Safety reviews have found low toxicity and minimal irritation potential even in leave-on use.

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 strong alkali used in tiny amounts to adjust the pH of cosmetics to safe, skin-friendly levels. At the pH found in finished products, sodium hydroxide is neutralized and well tolerated.

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.

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.

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.

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 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 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 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 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.

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.

Cinnamal is a fragrance compound found naturally in cinnamon bark oil and is one of the 26 allergens EU rules require to be named on labels above set thresholds. It is a recognized skin sensitizer in patch-test studies, so people with fragrance allergies may want to avoid products listing it.