Shampooing Couleur — ingredient safety report

• Allergy risk:Fragrance is the single most common cause of cosmetic contact allergy.
• Irritation:Frequent trigger of stinging and redness on reactive skin.

An umbrella term that can hide dozens of undisclosed scent chemicals. Fragrance is the leading cause of allergic contact dermatitis from cosmetics, and dermatologists routinely advise fragrance-free products for eczema, babies and sensitive skin.

• Irritation:The reference irritant used in dermatology research; strips barrier lipids.

A powerful foaming cleanser so reliably irritating that dermatology studies use it as the standard positive control for skin irritation. Fine for many in rinse-off use, but a poor match for dry, sensitive or eczema-prone skin.

• Allergy risk:Potent sensitizer, typically blended with MIT (Kathon CG).
• Irritation:Corrosive in concentrate; irritating at use levels.

The chlorinated partner of MIT, restricted in the EU to rinse-off products only. A leading cause of preservative contact dermatitis worldwide.

• Allergy risk:Caused an epidemic of contact allergy; banned in EU leave-on products.
• Irritation:Irritating even in people without allergy.

A preservative behind one of the largest contact-allergy epidemics in cosmetic history. The EU banned it from leave-on products and restricts it in rinse-off products to 15 ppm.

• Irritation:Milder than SLS but still drying for compromised skin.

The gentler cousin of SLS used in most mainstream shampoos and washes. Its manufacturing can leave trace 1,4-dioxane, which reputable makers strip out — an issue of quality control rather than the ingredient itself.

• Allergy risk:EU-declarable allergen with well-documented sensitization.

A rose/geranium scent molecule and one of the more frequently positive fragrance allergens in patch testing.

• Allergy risk:American Contact Dermatitis Society Allergen of the Year 2018.
• Irritation:Can irritate compromised skin at higher concentrations.

A workhorse humectant and penetration enhancer that is fine for most, but a recurring culprit in eczema patients' patch tests.

• Allergy risk:Named Allergen of the Year 2004; impurities (amidoamine) drive most reactions.

A mild coconut-derived surfactant in countless 'gentle' cleansers. Most allergy is caused by manufacturing impurities, so quality varies by brand.

• Allergy risk:EU-declarable fragrance allergen.

A rose-type scent component on the EU's mandatory-declaration allergen list.

• Irritation:Occasional stinging and irritation, mostly around eyes and on damaged skin.

Today's most common preservative, considered safe by the SCCS up to 1%. French authorities advise avoiding it in wipes and diaper-area products for children under 3 as a precaution.

• Environmental impact:Synthetic polymer counted as a microplastic under the EU restriction when in particle form.

A common film-forming polymer scrutinized under the EU's microplastics restriction; skin safety itself is well established.

• Irritation:Occasional transient stinging or redness on sensitive skin.

A mild food-grade preservative usually paired with sodium benzoate; well tolerated by most skin types.

• Environmental impact:Not biodegradable; accumulates in the environment via wash-off.

The workhorse silicone — inert and non-sensitizing on skin (even FDA-approved as a skin protectant), with persistence in the environment as its main criticism.

• Environmental impact:Poorly biodegradable; can remobilize heavy metals in waterways.

A metal-binding stabilizer that is safe on skin at the tiny amounts used; its criticism is environmental persistence.

• Irritation:Can cause transient, non-allergic flushing/stinging on reactive skin.

A food-grade preservative generally regarded as one of the gentler options; occasional non-immune stinging is its main drawback.