Fragrance is a chemical combination of essential oils and other scent chemicals. Fragrance is an artful and expensive product resulting from the blending of certain odoriferous substances in specific proportions. It has been a part of perfumery, or the artful application of scent, since ancient times. Fragrance is used in the creation of such products as perfumes, colognes and aftershaves. The word fragrance can also be used figuratively to refer to the smell of something, or a person’s scent.
Perfumes are a mixture of natural and synthetic essential oil extracts combined with solvents. They can contain tens to hundreds of ingredients, including a wide range of aromatic plant extracts and other organic and synthetic compounds. They can have a light to heavy concentration level, with perfumes containing high levels of aromatic compounds usually referred to as parfum. Toilet waters and colognes are usually lower in concentration, with eau de toilettes ranging from 8-15% and eau de colognes at about 4% to 5%.
In addition to the perfume base, a perfume may also contain a middle note and a top note. The head note, or top note, is the first impression a person receives when they smell the perfume. It is comprised of small, light molecules that evaporate quickly after the perfume has been applied. Middle notes are a bit longer lasting than the head notes and are typically composed of larger, more complex molecules such as flowers and spices. A common middle note is jasmine, which provides a rich, full and balanced scent [3,5].
The bottom or base note provides the long-lasting impression of the perfume. The scent of the base note is slower to develop than that of the middle notes, and is made up of heavier molecules such as resins, musks and woods. It appears 20-60 minutes after the application of the perfume and lasts 2-4 hours. The fragrance of a perfume is often altered by the weather and the wearer’s mood. Perfumes can become stronger when worn in hot weather because they evaporate more slowly, while a lighter perfume will have softer sillage when a person is wearing it in colder temperatures.
From a neurobiological perspective, there is no empirical evidence that perfume elicits a reward value in humans. However, it is possible that the sensory experience of a favored perfume activates the olfactory cortex (OFC) and possibly sub-regions of the OFC associated with reward processing. The OFC is also innervated by dopaminergic neurons, and it is possible that the neurotransmitter dopamine plays a role in the sensation of reward.
Perfumes were very popular in the Renaissance and into the nineteenth century, when both men and women wore them regularly. However, as a result of the spread of germ theory, a shift in public perception occurred and perfume wearing became gender stereotyped. Sweet floral blends were perceived as feminine, while sharper, masculine perfumes such as pine, juniper and cedar became associated with masculinity. As a result of this change in public perception, the use of perfumes declined.