Shampoo — ingredient safety report

• 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: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.

• 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.

• 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; oxidized linalool is a common patch-test positive.

A floral scent molecule found in lavender and many essential oils. It oxidizes on air exposure into strongly sensitizing compounds, which is why it must be declared on EU labels.

• Allergy risk:One of the 26 EU-declarable fragrance allergens.
• Irritation:Mild irritation possible at higher concentrations.

A preservative and fragrance component that must be declared on EU labels because it can trigger contact allergy in a small share of users.

• Allergy risk:EU-declarable fragrance allergen.

A floral fixative on the EU allergen list, with early-stage evidence of weak hormonal activity being evaluated by regulators.

• 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.