Why do some fragrances last longer than others?

Fragrances are typically made up of notes – top notes, heart notes (also known as middle notes) and base notes. It is the blend of these three notes that creates a rich and sophisticated scent.

The three notes can be thought of as being part of a triangle or pyramid. At the top of the pyramid lies the top notes, which give us the first impression. Top notes are often fresh and consist of the most volatile molecules.

After 5–20 minutes, the top notes can dissipate, gradually exposing the heart notes, which reveal the character or "heart" of the fragrance. Heart or middle notes can typically last 5–6 hours.

At the bottom of the pyramid lies the base notes, which are the last to fully expose themselves during the "dry down" but they often overlap with the heart notes. Base notes have heavier molecules that stay around for longer – sometimes for up to 24 hours. Some oils, like pure oud, can last for days!

Since the molecules of the top notes are lighter than the heart and base notes, they are more volatile and the first to evaporate. If a fragrance is made up mostly of top notes, it might smell great but it won't last very long. This is one of a number of reasons why a scent may not last long, in comparison to another.

Other factors that affect longevity are fragrance quality or concentration, skin type, gender, and where the scent is applied.