It’s perfectly fine to blend essential oils with fragrance oils for the purpose of making candles and melts. Keep in mind that some essential oils smell unpleasant when burned, so thoroughly burn testing your candles is important. If the scent throw of your blend shifts when the flame is lit, consider making wax melts with your blend instead.
When blending essential oils for use in soap, lotion, or other body care products, refer to their IFRA certificates to determine the maximum safe usage percentage. Compare the maximum usage percentages of the oils in your blend, and follow the lower recommended percentage for the entire blend.
For example, Matcha and Bergamot’s IFRA sheet recommends no more than an 8% fragrance load for soap, while the IFRA sheet for Tea Tree essential oil recommends a 1% maximum. So, your max usage amount for a blend of Matcha and Bergamot and Tea Tree in soap would be 1%.
For more information about determining safe usage amounts of essential oils in body care products, please see our Learning Section article: How To Use The IFRA Certificate.