In the study of soapmaking, one of the most interesting topics is essential oils. Unlike fragrance oils, which are mainly synthetic, essential oils are the natural oils from plants. Like fragrance oils, essential oils contribute fragrance to your soap formulas, but they may also have the benefit of aromatherapy, offering health benefits. The more you know about the properties of essential oils, the more you'll be able to create soaps that soothe, relax, invigorate, and improve mood.