The main drawback of bergamot oil is photosensitivity (sensitivity to light). Cold-pressed bergamot oil contains a phototoxic constituent, so skin topically exposed to bergamot oil may become very photosensitive, developing itching, redness and dark pigmentation — and in some cases, even burning — when exposed to ultraviolet light. The culprits are psoralens found in the cold-pressed oil (primarily bergapten, a phototoxic psoralen also known as 5-methoxypsoralen (5-MOP) or bergamot camphor).[1][2] Further, it’s possible for the phototoxic psoralens found in BEO to induce skin cancer after exposure to ultraviolet light. Because of bergapten’s phototoxicity, the International Fragrance Association recommends that the concentration of bergamot oil in products applied to sun-exposed skin be limited to 0.4%, targeting a maximum of 15 ppm of bergapten in the final product.[3] Therefore, when applying bergamot oil to any skin that may be exposed to the sun, care should be taken to use only bergapten-free bergamot oil, even if there will be a few days between bergamot use and sun exposure. There have been case reports of people who have developed phototoxic skin reactions (burning, blistering) after using bergamot-containing preparations, such as bergamot massage oil, directly on the skin, and then spending time in the sun 48–72 hours later.[4]