Psidium Guajava Seed Oil

Psidium Guajava (guava) seed oil is primarily an emollient/occlusive lipid used at low-to-moderate levels to support barrier function, but as a botanical oil it contains minor unsaponifiables that can provoke irritation or allergy in reactive or eczema-prone skin. Clinical patch-test data for this specific oil is limited, so safety assessment relies on its class behavior: most seed oils are generally tolerated yet have a meaningful minority of sensitization/irritation reports compared with inert carriers. Given the uncertainty and the higher-risk population, I rate it as mild—usually tolerated, but occasional sensitivity is plausible and patch testing is prudent. Safety Notes: In mass-market and indie formulations, Psidium Guajava Seed Oil most often appears as a minor emollient/marketing botanical in blends at trace-to-low levels (~0.01–0.5%), especially in lotions, shampoos/conditioners, and facial serums where it is one of many plant oils. At the high end, consumer-available single-ingredient guava seed oil products (sold as 100% pure oil) and anhydrous balms/oil serums can reach 50–100%, with 100% representing the neat oil; regulatory frameworks generally do not set a specific maximum for this cosmetic plant oil, so practical limits are driven by sensorial feel, oxidation management, and leave-on wearability rather than legal caps.