Oenothera Biennis Oil

Oenothera biennis (evening primrose) oil is an emollient rich in linoleic and gamma-linolenic acids, typically used at a few percent up to higher levels in moisturizers, and is generally well-tolerated in sensitive and eczema-prone skin. However, as a botanical lipid it can still trigger irritant or allergic contact dermatitis in a minority of reactive individuals (including from oxidation byproducts if the oil is aged/poorly stabilized), so it is not truly inert. Given its overall favorable tolerability but non-zero sensitization/irritation potential, it fits best as a "gentle" (0.3) ingredient. Safety Notes: In mass-market leave-on creams/lotions and serums, Oenothera biennis (evening primrose) oil is frequently used as a minor emollient/claims ingredient around ~0.05–1%, with rinse-off cleansers often at the very low end due to surfactant systems and cost/feel constraints. Many facial oils, body oils, and “booster” products use it as a primary lipid in the ~5–30% range, and consumer-available single-ingredient oils are sold as 100% Oenothera biennis oil (neat, leave-on). No specific EU/FDA cosmetic maximum is set for this fixed oil; practical upper limits are driven by oxidation stability (high linoleic/GLA content) and sensorial performance rather than regulation.