Fragrance is the combination of chemicals that give each perfume or cologne its distinct scent. These chemicals are often called “fragrance oils” or simply “fragrance.” Perfumes and colognes contain a mixture of fragrance oils derived from natural raw materials, as well as other ingredients that help improve marketability, enhance stability and maintain shelf life. These ingredients may include solvents, UV-absorbers, preservatives and dyes. Some of these ingredients may cause skin sensitivity or allergic reactions.
The word fragnance is a French term meaning “fragrant mixture.” Fragrances are usually pleasant, but they can be harsh or unpleasant. Fragrance includes both natural and synthetic odorants, and many are derived from natural raw materials such as plants and spices or synthetically manufactured using a wide variety of chemical compounds. Fragrance is most often applied directly to the skin, but may also be added to hair products and other scented household products.
There are five main groups of perfumes, loosely based on their concentration of fragrance oils. The highest concentration is called parfum, which has 20-30% fragrance oils and is used in perfume, cologne and aftershave. The next concentration down is eau de toilette (EDT), which has 10% fragrance oils. Eau de cologne (EDC) has 5% and eau de spray (EdS) has 1%. The remaining two concentrations are eau de parfum (Pf) and eau de parfum concentrée (EdC).
A perfume can be classified by its family, which is a general classification of the fragrance type. The most common families are citrus, floral and woody. The family of a perfume is important because the scents in that family are similar and interact well with each other. A perfume can be altered by changing its top note, middle note or base note.
It is difficult to categorize a perfume into a single family because all perfumes will contain aspects of several families. Moreover, the grouping of perfumes into families does not necessarily correspond to how perfumers develop their creations.
For example, a perfume designated as a citrus fragrance will contain both citrus and spice notes, while a perfume that is a single flower scent will have subtle undertones of other aromatics. Manufacturers who publish perfume notes typically present the components of a fragrance as a pyramid,[1] which is a useful visual representation of the scent’s structure.
Although the FDA regulates cosmetic products in the US, it does not require that companies reveal individual fragrance chemicals or their dilutions in order to protect fragrance trade secrets. These exemptions contribute to a gap in consumer understanding about the potential harms from fragrance chemicals.
Perfumes and colognes also contain other ingredients that do not affect their smell, such as surfactants and stabilizers, which are used to help the oil spread evenly over the skin. They also contain alcohol to improve the aeration of the perfume and enhance its durability. A few of the many thousands of fragrance chemicals available in the market can cause skin sensitivity or allergic contact dermatitis when exposed to the skin, especially for long periods of time. These chemicals include benzene derivatives, aldehydes and toluene, and synthetic fragrances can contain allergens such as linalool, hexyl cinnamal and geraniol.