A resin bees collect from plants, used for blemishes and 'glow'. Antimicrobial in the lab, little tested on skin, and a well-documented contact allergen.
Propolis is the sticky resin bees gather from tree buds to seal their hives. It is rich in flavonoids and caffeic acid esters, with antibacterial, antifungal and antioxidant activity in lab tests. Korean skincare uses propolis extracts in serums and toners for blemish-prone and dull skin.
Its composition varies with region and plant source, so two 'propolis extracts' can differ considerably.
Clinical evidence for propolis in cosmetic skincare is sparse — mostly lab work and small studies in wound care. Its allergy potential, by contrast, is well documented, with many reported cases of allergic contact dermatitis.
Reviews propolis's composition, biological properties and uses, and catalogues its contact allergy: sensitizing potential, products causing reactions, frequency, cross-reactions and the specific allergens involved.