Ingredients

Ethanol. Makes products feel light and dry fast, but high up the list in leave-on products it can dry out and irritate skin.

Also written Ethanol, Ethyl Alcohol

Denatured (drinking-unfit) ethanol. Makes products feel light and dry fast, but high up the list in leave-on products it can dry out and irritate skin.

Also written Denatured Alcohol, SD Alcohol, SD Alcohol 40

A powdery, violet-like scent ingredient and listed fragrance allergen.

A sulfate cleanser as strong as SLS. Can dry and irritate.

A jasmine-like scent ingredient and listed fragrance allergen.

A floral scent ingredient and listed fragrance allergen.

A sweet, floral scent ingredient and listed fragrance allergen.

Also written Anisyl Alcohol

Flavour — what gives toothpaste or lip balm its taste. Like fragrance, it's a blend the label doesn't itemise, and it can contain the same allergens.

Also written Flavor, Flavour

A balsamic scent ingredient (also used as a solvent). One of the fragrance allergens EU labels must name.

A sweet, balsamic scent ingredient. One of the fragrance allergens EU labels must name.

A faint, sweet scent ingredient that also absorbs a little UV. One of the fragrance allergens EU labels must name.

A synthetic antioxidant used in tiny amounts to keep oils fresh. Often listed next to BHA as a possible hormone disruptor; EU safety scientists reviewed it and allow it with strict limits.

Also written Butylated Hydroxytoluene

A longer-chain paraben. Like propylparaben, the EU has lowered its permitted concentration and bans it in leave-on products for the nappy area of young children, over possible hormone effects.

The molecule that makes cinnamon smell like cinnamon — and one of the more common fragrance allergens.

Also written Cinnamaldehyde, Cinnamic Aldehyde

A warm, hyacinth-like scent ingredient and listed fragrance allergen.

A lemony scent molecule and a known fragrance allergen.

A rose-like scent molecule and a listed fragrance allergen.

Neroli flower oil — an essential oil, there for scent. Essential oils are natural sources of the fragrance allergens labels must name (linalool, limonene, geraniol…) and can irritate sensitive skin.

Bergamot essential oil, the scent of Earl Grey. Ordinary bergamot oil can cause burns and dark patches on skin in sunlight; many brands use a bergapten-free (FCF) grade.

Also written Bergamot Oil

Sweet orange essential oil — nearly all limonene, which becomes a stronger allergen as it oxidises in air.

Also written Orange Oil, Orange Peel Oil, Sweet Orange Oil

Lemon essential oil, rich in limonene. Cold-pressed lemon oil can make skin react to sunlight, so take care in the sun with leave-on products that contain it.

Also written Citrus Medica Limonum Peel Oil, Lemon Oil, Lemon Peel Oil

A foam booster made from coconut fatty acids and diethanolamine. It can carry traces of DEA, and it's listed as possibly carcinogenic (IARC group 2B). Common in shampoos.

Also written Cocamide Diethanolamine, Coconut Oil Diethanolamine Condensate

Coconut oil. A rich emollient that works well on body and hair, but tends to clog pores on the face.

Also written Coconut Oil, Cocos Nucifera (Coconut) Oil

A sweet, hay-like scent molecule and a listed fragrance allergen.

Octinoxate. A UVB filter under review for possible hormone effects and banned in some reef areas.

Also written Octinoxate, Octyl Methoxycinnamate

Eucalyptus essential oil. Fresh and cooling, but it can irritate sensitive skin, and like other essential oils it becomes a stronger allergen as it oxidises.

Also written Eucalyptus Oil

The clove-scented molecule; a listed fragrance allergen.

Treemoss, a perfume base like oakmoss, and a strong allergen for the same reasons.

Also written Evernia Furfuracea (Treemoss) Extract, Treemoss Extract

Oakmoss, a classic perfume base. A strong allergen — the EU limits the compounds in it that cause most reactions.

Also written Evernia Prunastri (Oakmoss) Extract, Oakmoss Extract

A soft floral scent molecule found in many flowers and essential oils. One of the fragrance allergens EU labels must name.

A rosy scent molecule and a well-known fragrance allergen.

An alpha-hydroxy acid (AHA) that exfoliates the surface for smoother, brighter skin. Can sting and increases sun sensitivity — wear sunscreen.

A jasmine-like scent molecule and a listed fragrance allergen.

A UVB filter the EU limited to 7.34% in face products after reviewing possible hormone effects.

A fresh, lily-like scent ingredient. A well-known allergen, limited to small amounts in the EU.

A spicy, carnation-like scent ingredient and a strong sensitizer, limited to small amounts in the EU.

A light, fast-absorbing ester. Known to clog pores in acne-prone skin.

A thin emollient ester closely related to isopropyl myristate; can clog pores in acne-prone skin.

Wool wax. An excellent moisturiser, but a known contact allergen for a small number of people.

Also written Adeps Lanae

The alcohol part of wool wax. A good moisturiser, and the part of lanolin most often behind lanolin allergy.

Also written Lanolin Alcohols, Wool Wax Alcohols

Lavender essential oil. Natural, but rich in linalool and a known cause of skin reactions.

Also written Lavandula Angustifolia (Lavender) Oil, Lavender Oil

A citrus scent molecule. Oxidises in air into compounds that commonly cause contact allergy.

Also written D-Limonene

A floral scent molecule from lavender and many other plants. Becomes a stronger allergen once exposed to air.

Tea tree essential oil. Some evidence against spots, but a common cause of contact allergy — especially once it's old and oxidised.

Also written Tea Tree Oil

Peppermint oil gives a cooling tingle — which is mild irritation. Not ideal for sensitive skin.

Also written Peppermint Oil

The cooling compound in mint. That fresh tingle is mild irritation — pleasant for most, not ideal for sensitive or broken skin.

A green, violet-leaf scent ingredient and listed fragrance allergen.

Also written Methyl Heptine Carbonate

A UVB filter that stabilises others. Can cause contact allergy, and it slowly breaks down into benzophenone in the bottle.

The key ingredient in most permanent dark hair dyes and a potent allergen — patch test every time, and never use it on skin ("black henna").

Also written PPD

A blend of scent chemicals the brand doesn't have to itemise. Fragrance is the most common cause of allergic reactions to cosmetics — skip it if your skin is sensitive.

Also written Fragrance, Perfume

Geranium flower oil — an essential oil, there for scent. Essential oils are natural sources of the fragrance allergens labels must name (linalool, limonene, geraniol…) and can irritate sensitive skin.

A plastic used in scrubs and as a thickener. As microbeads it's a microplastic — banned in rinse-off products in many countries.

A longer-chain paraben. The EU has lowered its permitted concentration and bans it in leave-on products for the nappy area of young children, over possible hormone effects.

A vitamin A derivative with strong evidence for smoothing lines and improving texture. Often irritating at first; use at night with sunscreen by day, and avoid during pregnancy.

Sandalwood oil — an essential oil, there for scent. Essential oils are natural sources of the fragrance allergens labels must name (linalool, limonene, geraniol…) and can irritate sensitive skin.

A strong, foamy cleanser. Effective but stripping — a common cause of irritation and dryness, especially in leave-on or face products. Used as an irritant in skin testing.

Also written SLS

Cocoa butter. Rich and protective for dry body skin, but can clog pores on the face.

Also written Cocoa Butter, Theobroma Cacao (Cocoa) Seed Butter

A hair-dye ingredient used in place of PPD in many permanent dyes. It's a strong allergen too — many people allergic to PPD react to it. Patch test before every colouring.

Also written 2,5-Diaminotoluene, PTD