Fragrance is the term for the blend of more than 3,500 chemicals that give some personal care, cleaning and other products their distinctive smell. Some fragrance ingredients are toxic, and exposure to them can cause a range of health harms, from skin rashes to breathing problems. Unlike most other skincare products, fragrances aren’t subject to the same safety testing as drug and food additives. And manufacturers aren’t required to list the perfume ingredients on their labels.
The word fragrance can imply the sweet, pleasant smells of plants and flowers, but it’s more often used to describe any odor-generating product—from soaps to shampoos to candles. It’s also sometimes used interchangeably with parfum and perfume.
Perfumes today are typically composed of three structural parts: top, middle and base notes. Top notes are the first scents to emerge after a person applies perfume, but they evaporate quickly (about 30 minutes after application). Middle notes, which linger longer than top notes, help provide body and consistency. They also serve as a counterpoint to the sharp, often acrid scents of some bottom notes.
Modern perfumes usually combine natural essential oils derived from roots, bark and other parts of plants with synthetic odorants. The synthetics offer a broader palette of scents than the traditional ones. For example, aliphatic aldehydes can lighten a floral bouquet like rose and jasmine by providing a clean, soapy or lemony zing, as they do in present-day perfumes such as those from Prada and Serge Lutens.