Why does the Chanel No. 5 that I bought twenty years ago smell different from the bottle I got for my birthday last week?
Sometimes the producer has to change the formula.
In many *countries, before a perfume is released, the formula must comply with the regulations set out by the International Fragrance Association (IFRA).
The formulation is examined to verify that the ratios of ingredients are safe, even if they are natural oils such as rose or jasmine. IFRA has gone so far as to almost ban the use of natural rose in perfumes and cosmetics, because of a naturally occurring chemical called methyl eugenol, which is a known carcinogen.
Studies have shown that in certain amounts it causes tumours in mice and rats, there is no evidence to date that it has the same effect in humans, but err on the side of caution they must.
Perfumes are also subject to ongoing testing and changes in regulations, even after release. IFRA may require a perfume house to limit certain ingredients, or even eliminate them entirely. With Lilial and its cousin Lyral (used to recreate the scent of Lily of the valley), they previously deemed these patented ingredients safe but restricted. But now if you create a perfume using either of these ingredients you will not get it approved for consumer retail and if you have any perfumes that are currently on the market, you'll need to withdraw them because studies show the above ingredients cause toxicity in mice, and IFRA is now banning their use.
Back in 2014, IFRA forced Chanel to change their No. 5 formula because they found that one of its ingredients was a skin irritant. This means that the bottle you bought a long time ago doesn’t smell the same as the newest bottle you just received, simply because the ingredients are different.
*some countries that must comply with IFRA are Europe, UK and some countries in the Middle East like the UAE and KSA. Most large perfume houses are members of IFRA meaning that the scents they create are compliant, indie perfumers do not need to be a member but if you are creating a perfume for retail sale you will need a COSMETIC PRODUCT SAFETY REPORT (CSPR) to prove its compliancy and get it registered on the mandatory European Cosmetics Notification Portal.
If the formula has not been altered, there is a second plausible reason for the difference in scent. Perfumes go through a process called maceration, which is key to developing fragrance.
Over time, a perfume’s aroma continues to mature. Maceration involves letting the fragrance develop for up to *6 months, during which the scent and performance is checked to establish if and when a perfume is ready for sale.
But perfumes continue to macerate even after bottling, which explains why the older version of your perfume smells a little different from your newer one.
When creating your own scents, maceration is an important factor. Be patient and let your fragrances develop to their full potential rather than be in a rush to get them on the market.
*this time frame was plausible decades ago when time wasn’t such a constraint, unfortunately in the fast-moving world that we live in there is no time to delay and perfumes are rushed out to market because the competition is fiercer than ever.
Check out the FRAGRANCE 101 course at The Scent Academy by Melanie Jane