Inonotus Obliquus Extract

Inonotus obliquus (chaga) extract is typically used at low concentrations in cosmetic formulas as an antioxidant/soothing botanical; available human data suggest low irritancy for most users, but evidence is limited compared with well-characterized actives. As a complex natural extract containing multiple bioactive compounds, it carries a small but real risk of irritation or allergic contact dermatitis in highly reactive or eczema-prone patients, especially when combined with other potential irritants in a routine. Safety Notes: Inonotus obliquus (chaga) extract is typically used as a marketing/antioxidant-support botanical in leave-on facial products at very low levels (often ~0.001–0.1%) when supplied as a dilute liquid extract or as part of a blended “mushroom complex,” and it can appear similarly low in rinse-off cleansers where contact time is short. Higher-strength consumer serums, ampoules, masks, and some creams using concentrated glycerin/butanediol extracts or higher active loading commonly reach ~1–3%, with a small number of OTC “concentrate” formulas pushing to about ~5% before sensorial, color/odor, and stability constraints (solids/viscosity and potential tack) typically limit further increases.