Methylparaben

Methylparaben is a preservative typically used at low concentrations (generally well under 1%) and has low irritancy in controlled human patch testing, with most users tolerating it well. However, in highly sensitive or barrier-impaired populations (e.g., active eczema), rare irritation or allergic contact dermatitis can occur, so it cannot be scored as “very gentle” or “exceptionally gentle” for all patients. Safety Notes: In current and legacy mass-market cosmetics, methylparaben is commonly used at very low levels (~0.01–0.05%) as part of a paraben blend (often paired with propylparaben/phenoxyethanol) in both leave-on lotions/creams and rinse-off cleansers. High-strength OTC products (especially older or preservative-challenging emulsions and some salon/consumer-available creams) have been observed using methylparaben up to ~0.25–0.30% to meet preservation requirements. EU cosmetics rules allow methylparaben up to 0.4% as an individual paraben (0.8% total for mixtures), but real-world consumer products typically do not exceed ~0.30% for methylparaben alone.