Essential oils are valuable natural products used as raw materials in many fields, including perfumes, cosmetics, aromatherapy and phytotherapy, spices, and nutrition. Essential oils are complex mixtures comprised of, in some cases, more than 250 single compounds. Each of these constituents contribute to the beneficial or adverse effects of these essential oils. Therefore, the intimate knowledge of essential oil composition allows for a better and specially directed application. For example, an essential oil with a high content of a relaxant cannot be applied for activating purposes. An essential oil containing furocoumarines cannot be used as perfume material for suncreens. As a natural product, essential oil composition depends on climate, soil, harvesting time, method of production and similar factors. The different chirality of main constituents governs the uses of essential oils and should be considered as well.
A series of factors influencing the composition of essential oils are discussed under the general topic of cosmetology applications. Because essential oils are naturally occurring fragrance mixtures, the question is, why are fragrances used in cosmetic products? To answer this, we must answer the following:
• One must not forget that many cosmetic raw materials possess an odor that cannot be described as pleasant, sometimes smelling outright disagreeable. Because of this, one main goal of any fragrance addition to a cosmetic product is to conceal, to mask a bad smell or a malodor inherent to ingredients. • The application discipline of a cosmetic product is often increased by a pleasant fragrance. This is beneficial to both partners: the user, who gains efficacy by following the recommended application schedule, and the producer, who can sell more of his product.