Fragrance is a combination of chemicals that give perfume or cologne its distinctive scent. Companies that manufacture perfume or cologne purchase fragrance mixtures from fragrance houses (companies that specialize in developing fragrances). These mixtures contain raw materials derived from natural products and petroleum, as well as stabilizers, UV-absorbers, preservatives, dyes and other chemicals. The FDA does not require labeling of specific chemicals used in fragrance ingredients. This protects companies from public disclosure of fragrance ingredient information and sustains a loophole in which companies may hide certain chemicals that have been linked to health problems including cancer, reproductive and developmental toxicity, allergies and sensitivities.
The main distinction between a perfume and a cologne is the concentration of perfume oils in the product. A perfume contains a higher concentration of oil, typically between 20 and 30 percent, than does a cologne, which generally has an oil content of only 2 to 4 percent.
Perfumes are usually divided into three structural components: a top note, or head note, which provides the initial impression and evaporates quickly; middle notes, also called heart notes, which form the body of a perfume and remain for a longer period of time than the top note; and base notes, which provide depth and solidity to the perfume. [1]
In addition to these structural components, many perfumes are classified based on identifiable dominant odours. For example, floral blends evoke the aroma of flowers such as rose, jasmine or lily of the valley; spicy fragrances include odours such as clove or cinnamon; and woody fragrances have an aroma that is reminiscent of vetiver (a grass known as khuskhus) or sandalwood. Gourmand perfumes are a relatively new category that take their inspiration from the food world and feature synthetic edible odours such as honey, chocolate or vanilla.