Perfume is an odorant designed to be applied to the skin. It is intended to be a pleasant, desirable scent that enhances self-appeal and self-confidence. Perfumes have also been reported to have therapeutic properties reducing stress and anxiety, increasing cognitive function, and even improving pain tolerance through the activation of opioid pathways [1, 2].
The process of creating perfume begins with the extraction of essential oils from raw materials such as fruits, flowers, spices, herbs, leaves, bark, wood and roots. These essential oils are then diluted with a solvent such as ethanol or a mixture of ethanol and water. Modern perfumes contain tens to hundreds of different ingredients including: a) natural or synthetic aromatic compounds that are classified by their structural group (alcohols, esters, aldehydes and terpenes); b) a fixative that is a naturally occurring or synthesized substance which slows the evaporation of the odorant compound; c) a volatile oil which gives off the smell; and d) a carrier for the fragrance – typically a mixture of jojoba and almond oils.
Once the essential oils are combined they are sprayed on the skin and the trail of odor that is left behind is called the sillage. The sillage is the result of the interaction of three sets of fragrance notes: the top notes, middle notes and base notes. Top notes are the earliest scents to be perceived and consist of small molecules that evaporate quickly. Middle notes are the heart of the perfume and are composed of more complex molecules that fade over a longer period of time, and the base notes are large and heavy molecules that last longest, sometimes up to 24 hours after application.