Why doesn’t my favorite perfume smell the same anymore? The mysterious task of fragrance reformulation

The day the European Union placed limits on how much oakmoss perfumers could include in their creations, some feared it would mark the end of their craft. “That was a tremendous blow because oakmoss is essential in chypres and fougères,” says Ramón Monegal, perfumer and holder of the Iris Chair of Florence at the Perfume Academy, referring to two of the most common fragrance families.

The ingredient brings warmth and depth, with earthy, woody, and damp nuances — but it’s also a potential irritant that can cause dermatitis in some individuals. Although oakmoss had been used as an aromatic for centuries, regulators decided to eliminate the risk by sharply limiting how much could be used in any given formula. Even if that meant narrowing the perfumer’s palette.

Guidelines from organizations such as the International Fragrance Association (IFRA) establish safety standards and best manufacturing practices to ensure that ingredients are used responsibly, taking into account their environmental and health impacts.

All components are subject to toxicological and dermatological testing, and if any doubts arise about a substance, its use is either limited or eliminated altogether. However, each new regulation doesn’t just apply to future products — it also affects existing fragrances, requiring perfume houses to review their entire catalog and reformulate products as needed, all while trying to preserve the original scent.

Making things even more challenging, IFRA updates its standards frequently — every two to three years. “The current standard is IFRA Guide 50, and the next edition is already underway,” says Belén Carazo, scientific and technical director of Spain’s National Association of Perfumery and Cosmetics (Stanpa).

Meanwhile, the European Union also periodically revises its Cosmetics Regulation through what are known as Omnibus Regulations, which introduce new usage conditions or ban ingredients based on the latest scientific findings.

An invisible job

Reworking fragrances to comply with new regulations is one of the lesser-known aspects of a perfumer’s work — yet it takes up a significant portion of their time. It’s no easy task, but innovation is making it more manageable.

“Traditionally, this was done by hand, but today, technology plays a crucial role,” says Carazo. “From advanced spreadsheets to specialized software systems, and now artificial intelligence, which is revolutionizing the industry.”

In the case of oakmoss, that note has almost universally been replaced with a synthetic molecule called Evernyl. But oakmoss isn’t the only ingredient under scrutiny. The company PyD had to reformulate its iconic Halloween Eau de Toilette more than 20 years after its creation — once in 2018 and again in 2021.

“We worked with perfumers to achieve an identical perfume, replacing one molecule with a fresh floral note for an equivalent one that gives this transparent floral effect,” says Anaïs Paillard, fragrance development coordinator at the company. “We also reduced a couple of ingredients with citrus notes and another with an aromatic note with a lavender effect. We worked to balance the formula using equivalent substitutes.”

In this task, every master has their own tricks: “When an ingredient gets restricted, the first thing I do is remove it from the composition and observe the result. It will be different, but I use my evaluation criteria to decide whether it can work without it or not,” says Monegal, a fourth-generation perfumer from a family central to the history of fragrance in Spain through Myrurgia.

If the result isn’t satisfactory, the nose looks for a way to replace or complement it, because the structure of a perfume is all about balance: “Sometimes you can compensate by blending two other components, or sometimes there’s a substitute that serves the same function,” says Monegal.

She continues: “When it comes to a natural ingredient, the usual path is to look for synthetic alternatives. I know the nuances may be different, but our sense of smell isn’t as sharp as that of animals, and the customer’s nose isn’t trained. It’s also important to remember that there are differences between a perfume made with the 2023 harvest and one from 2024, because natural products depend on the sun, the rain, and even the day they’re harvested.”

When it’s impossible to adapt, the solution may be to discontinue a fragrance altogether or to create a new variation. Flankers (reinterpretations or evolutions of an existing fragrance) sometimes emerge as a way to expand a beloved fragrance line, to offer new takes on a successful scent (for example, with more intense versions), or to replace a classic that can no longer exist under current regulations.

“There are ingredients that have no substitute, and to solve the problem, the industry has developed a system using flankers, which are already made according to the new regulations, to eventually phasing out the original,” Monegal explains.

Avoiding ‘toxic’ ingredients

Today, there is a growing demand for more natural products, but also for safety and limits on problematic ingredients. The paradox lies in the fact that these two demands can often be at odds with each other.

“There’s a widespread perception that natural ingredients are always safer or more beneficial, but that’s not entirely true,” explains Belén Carazo, technical expert at Stanpa.

“Natural materials present particular challenges. Their composition can vary depending on factors like climate or the terrain where they’re grown, which makes standardization more difficult. Furthermore, some essential oils may contain allergens or sensitizing agents that require stricter regulation,” she continues.

These are measures aimed at ensuring both consumer safety and the sustainability of the resources used — but they also tend to favor synthetic molecules, which are easier to control in every sense.

For example, in terms of safety and cost: “A natural essence sourced from Indonesia or wherever might cost $120 this year and $150 the next,” says Monegal. “The industry can’t control the price of glass, cardboard, or plastics. But it can control the price of the perfume if it’s something entirely developed in a lab.”

It’s not about demonizing synthetic ingredients. In fact, modern perfumery was born when it became possible to synthesize molecules, allowing perfumers to imagine beyond the limits of nature. But relying solely on the convenience of synthetics isn’t the answer, either.

Much would be lost, warns Monegal: “A synthetic scent sometimes has a linear aroma and doesn’t offer the expansive result that a natural product can provide.”

It’s also worth noting that regulation doesn’t only apply to natural ingredients — synthetic molecules can be restricted too, though perhaps less often. That was recently the case with heliotropin, a component that provides a floral note but is also used in the production of synthetic drugs. “It was clear they would end up restricting it. When I used it, I had to inform the police of all the quantities it included,” recalls the perfumer.

The debate is interesting, but also complex — which is why many prefer not to discuss it openly. One shared goal does remain, however: to continue creating beautiful, problem-free products and to keep evolving, says Monegal: “The industry has learned how to adapt, and the restrictions have helped to hone inventiveness and creativity.”

Sign up for our weekly newsletter to get more English-language news coverage from EL PAÍS USA Edition