This is a major revolution in the world of fragrance. Nobody wants to talk about it out loud.

Have you ever felt like your favorite fragrance… simply changed? Same bottle, same name—but the note that once seduced you now sounds different. It's not your imagination. Reformulation is behind this quiet revolution in the world of perfume.

Have you ever reached for a bottle of your beloved perfume , sprayed it, and... felt like the blackness had vanished? Hello, where's my beloved fragrance? Maybe it's a faulty copy? Or has it faded with time? Nothing could be further from the truth. Behind this subtle (or not-so-subtle) change may lie the silent but very real hero of modern perfumery – fragrance reformulation , a process the industry prefers to keep quiet about, yet which transforms the face of many classics.

Perfumes , though enclosed in a glass bottle, exist in a world subject to regulations, trends, and scientific discoveries. This means that their formulas... are not set in stone. When the European Union restricted the use of oakmoss in fragrance compositions , many perfumers feared the end of an era. For centuries, this ingredient had imbued fragrances with depth and warmth, but it is also a potential allergen. Regulations forced creators to change their approach.

The International Fragrance Association (IFRA), among others, is responsible for fragrance safety. Every few years, the organization updates its guidelines, restricting or banning the use of substances that raise toxicological concerns. Each update (which appears every two to three years) requires perfume houses to review their archives and rewrite their legends. Each ingredient undergoes toxicological and dermatological testing , and if any concerns arise, its use is restricted or banned. This is where the invisible work of perfumers begins, unseen by consumers.

When one ingredient disappears, the scent sudoku begins.

"When a component is limited, I remove it and observe the effect. If the fragrance loses its balance, I look for a replacement or combination that will restore it," explains Ramón Monegal, Spanish perfumer and holder of the prestigious Iris Chair of Florence at the Perfume Academy.

for El Pais.