With our love for natural ingredients we sometimes neglect the fact that they could carry some hazards and could not be applied without any hesitation or limitation. One of these cases is the application of essential oils in natural cosmetics and perfumery.
Apart from the fact that they contain 13 of the 26 fragrance allergens which should be declared in the ingredients' list, some of them carry the risk of phototoxicity and photocarcinogenesis. These are basically essential oils from the rutaceae and apiaceae containing furocoumarins. Fourocoumarins trigger different reactions by being activated by UVA light (400-315 nm). These reactions could be from a reversible allergic reaction to an irreversible interchelation of Fourocoumarins and DNA which causes photocarcinogenesis. Because of this effect you should be extremely careful as you choose essential oils for your natural cosmetics and perfumery. IFRA and EU have guidelines for max. dermal dosage of essential oils containing furocoumarins when the part of the body coming into contact with the product (face, hands or body in case of suncare products) might be exposed to sun and UVA radiation. Even if you're not located in the EU and do not intend to sell your products in the EU it is reasonable to have a look at this list and consider the phototoxicity as you design your formulation.
These essential oils and the furocoumarins present in them are listed in the above infographic. Since most of these oils come from the citrus family, some citrus oils which do not cause phototoxicity because the concentration of furocoumarins is too low for an adverse reaction are listed as well.
Hope you'll like it and find it useful.
Resources:
Essential oil safety, Robert Tisserand, Rodney Young. Second edition, Elsevir
Photos: wikimedia.org
