Perfume is a combination of a water or ethanol solution with scented oils blended in. Perfume oil comes from either natural or synthetic sources. Synthetics are usually used to provide fragrance compounds that are not available naturally or would be too expensive if extracted from natural sources. Perfume ingredients can also include colorants and anti-oxidants to improve marketability and extend perfume shelf life.
During the Renaissance and into the nineteenth century, perfume wearing was ungendered, with both men and women enjoying the luxury of scenting themselves. But the spread of germ theory, along with a cultural view that smells of filth carried disease, led to a decline in perfume use and a gender stereotype for specific scents: sweet floral blends were viewed as exclusively feminine, while sharper woody, pine or cedar scents became distinctly masculine.
Early perfumes were created by mixing oils of flowers, leaves and other plants in an oil base such as jojoba, almond or apricot kernel oil. Later, jojoba oil was replaced by the more potent perfume-grade alcohol ethyl hexane. Oils are obtained from plant materials using a variety of extraction methods, including steam distillation and solvent extraction. Some delicate oils require a technique called enfleurage in which petals are placed between layers of purified animal fats that become saturated with the flower’s fragrance, and then treated with alcohol to obtain a concentrated oil known as an absolute.
Modern perfumes are often composed of a combination of natural and synthetic aroma chemicals, along with essential oils and other ingredients such as resins, waxes, spices, and metals. Perfumes contain a wide variety of chemical scent families, including aldehydes (benzoic, cinnamic), hexanal, linalool, coumarin and eugenol. The chemical composition of a perfume can be very complex, and the chemistry involved is still being studied to determine its effects on human health and the environment.
Regardless of their source, all perfume ingredients, even those derived from plants, have the potential to cause allergic reactions in some individuals. Several organizations monitor and test fragrance ingredients to assess their safety. In the United States, these organizations are the FDA and IFRA.
In addition to the odorous properties of fragrance chemicals, many of these compounds have therapeutic properties and may be helpful in treating various conditions, including anxiety, depression, asthma, dermatitis and headaches. Moreover, a perfume’s odor can have an impact on one’s mood and can influence other people’s reactions to the wearer.
In one study, researchers asked a group of women to choose a perfume and report their subjective ratings of its perceived effectiveness at improving a certain emotion or state of mind. The results showed that the perfume had a strong effect on the women’s emotions, and that this impact was related to the odorant’s hedonic quality and its resemblance to the desired state of mind. The researchers concluded that a perfume’s hedonic quality may be important in its ability to evoke a desirable emotional response, and that the same concept might apply to other types of fragranced products such as cosmetics.