Irritant

Definition

An irritant is any substance that causes a non-allergic inflammatory reaction when it comes into contact with the skin. Unlike allergens, which trigger an immune system response in sensitized individuals, irritants can affect anyone if the concentration is high enough or exposure is prolonged. Common skincare irritants include alcohol denat (denatured alcohol), sodium lauryl sulfate (SLS), synthetic fragrances, essential oils (especially citrus), high concentrations of active ingredients (like retinoids or acids), and physical irritants like rough fabrics or excessive scrubbing. Irritation manifests as redness, stinging, burning, dryness, or peeling. The severity depends on the irritant's strength, concentration, duration of contact, and the individual's skin barrier health. Preventing irritation involves choosing fragrance-free, gentle formulations, introducing new active ingredients gradually, and maintaining a healthy skin barrier.

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