Pistacia Lentiscus Gum

Pistacia Lentiscus Gum (mastic gum) is a resinous film-former/perfuming botanical extract typically used at low levels, but resins and plant-derived gum fractions contain complex terpenoid components that can trigger irritant reactions and occasional allergic contact dermatitis in reactive or eczema-prone skin. Patch test literature and clinical experience with similar resinous botanicals support a non-trivial sensitivity risk despite “natural” positioning, especially with leave-on use and a compromised barrier. Given the potential for both immediate stinging and delayed sensitization in sensitive populations, I score it as mild rather than gentle. Safety Notes: In commercial skincare, Pistacia Lentiscus Gum (mastic gum) is most often used as a minor film-former/sebum-control/skin-smoothing active or as part of a supplier blend, with effective label-declared use levels commonly starting around 0.01–0.1% in leave-on serums, emulsions, and primers. Higher-strength consumer products (typically leave-on “pore refining” or mattifying treatments) have been marketed around ~1–2%, and the upper end observed in OTC products reaches about 3% where sensory, tack/film, and solubility/stability constraints usually become limiting. It is uncommon in rinse-off at meaningful levels because benefits are primarily film-forming/leave-on sensory, so the practical market maximum is driven more by aesthetics and formulation robustness than by regulatory limits.