Raiders of the Lost Scent is an excellent fragrance website which contains useful information about how to date older Guerlain perfume bottles. It recently received a letter from an anonymous ex-Guerlain employee, stating that since 2003 Guerlain’s boxes have featured a numerical code which makes it possible to track fragrance reformulations.

Monsieur Guerlain has now been able to obtain official confirmation from Guerlain headquarters that this code is indeed linked to the fragrance formula, and that changes to the code track "the evolution of our formulas in compliance with the regulations". The code is to be found just below the list of allergens printed on the back of Guerlain boxes, and Guerlain recently made the allergen list and formula code for each fragrance available on its website as well.

Shown above is a travel atomizer of Habit Rouge EdT with a production date stamp saying April 2017 and the formula code 07928, which it has had since 2013, next to its current formula code as shown on Guerlain’s website, which reads 11917. It means that Habit Rouge EdT has been reformulated at least once between April last year and today.

It should be noted that the formula code is strictly linked to the list of allergens, and not to any other, i.e., non-allergenic, components that go into the perfume. When a fragrance contains rose oil, for example, the allergens contained within rose oil must be labelled. If statutory regulations for what to label change, which they do quite often, the allergen list and formula code may need to be adjusted accordingly, although the formula is unchanged.

Allergens in fragrances include ingredients that cannot be smelled, like colourants, solubilizers, preservatives, and UV filters; reformulations that concern only such odourless ingredients will not be perceptible. Hence, a new formula number may not always indicate that the actual fragrance has changed, but only that it now uses a different type of, say, colourant. To complicate matters further, the formula code may also change if a fragrance is diluted, because some of the allergens will then fall below the critical volume percent threshold in the final product and therefore won't appear on the allergen list, even though the concentrate itself has not been reformulated. Conversely, changes made to the formula that don't affect the allergens will not result in a new formula number. An example of the latter would be if Guerlain replaces one ingredient with another ingredient that has the same allergenic properties as the one it replaces. For instance, one kind of bergamot may smell different from another kind of bergamot, but if their allergenic properties are the same, a switch from one to the other will not result in a new formula number. See the infographic below.

(May 2018)

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