Phytosterols

Phytosterols are lipid-derived skin-conditioning/barrier-support ingredients typically used at low concentrations (about 0.1–3%) in creams and serums, where they generally reduce irritation rather than provoke it. Human patch testing and clinical use data suggest a low incidence of irritant reactions, with allergy/sensitization being uncommon but possible in highly reactive or plant-allergic individuals due to source impurities. Given their overall favorable tolerability in eczema-prone skin yet non-zero risk in sensitized populations, a very gentle score is most clinically appropriate. Safety Notes: In consumer skincare, phytosterols are commonly used as barrier-supporting, anti-irritant lipid actives and appear at low levels (~0.05–0.3%) in moisturizers/cleansers where they function mainly as supportive emollient-lipid components within complex blends. Typical leave-on barrier creams and sensitive-skin serums more often land around ~0.5–2% (sometimes declared as plant sterols or within sterol-rich complexes), consistent with levels explored in cosmetic research for barrier and redness benefits. High-strength OTC specialty balms, body butters, and lipid concentrates marketed for very dry/eczema-prone skin can reach about ~3–5% phytosterols (or equivalent active sterol fraction), with higher levels becoming uncommon due to waxy feel, solubility/phase-behavior constraints, and cost rather than regulatory limits.