The truth is that the difference lies in the concentration of essential oils in the fragrance’s water and alcohol base. Perfumes contain a higher concentration of oils, typically around 20 to 30 percent, while the oil concentration in cologne is around 2 to 4 percent.
Eau de Cologne
Eau de cologne, or simply cologne, contains an oil concentration of 2 to 4 percent. The term is commonly reserved for light and fresh masculine scents, which are often fruity or musky and typically last a few hours. During the first hour, the middle notes that are the heart of the fragrance prevail. During the second hour, the base notes that comprise a fragrance’s body take over. This is called the dry-down period, and it’s when your body chemistry interacts with long-lasting fixatives to produce the true or final scent. Since eau de cologne has a lower concentration, the scent does not last as long, so you may need to reapply if you go out for after-work drinks or dinner.
Perfume
Perfume is the most intense fragrance commonly used, with a concentration of 20 to 30 percent. Also referred to as parfum, it can last as long as 24 hours after a single application. During this time, your body chemistry can change dramatically, so the final scent typically does as well.
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