Perfume darkens with age mainly due to oxidation and light exposure, both of which gradually change the chemical structure of certain ingredients, particularly natural extracts and some aromatic compounds.

What’s actually happening inside the bottle

Every time a bottle is opened, a small amount of air gets in, and the oxygen in that air slowly reacts with the fragrance oils over time, in a process similar to how a sliced apple browns. Certain notes are more prone to this than others, vanilla, resins and some natural extracts tend to darken more visibly than very light citrus or aquatic formulas. UV light accelerates the same process considerably, which is why a bottle kept in sunlight will often discolour far faster than an identical one kept in the dark.

Does a darker colour mean it’s gone off?

Not necessarily on its own, colour change alone doesn’t always mean the scent has spoiled, though it’s often an early sign that the formula is starting to shift. If the smell has also gone sour, sharp or noticeably different from when you bought it, that’s the more reliable signal to stop using it. Our perfume storage guide and complete guide to perfume cover ageing and storage properly.