Both, with regulations like REACH for example, it makes use of synthetic derivatives like Ambroxide (versus actual Ambergris extracts) compulsory in certain international locations, this will impact longevity on the skin. Also with recent buy out of Creed by a large multinational luxury goods house (Gucci/Kering/Blackhorse), this’ll by definition change international supply chain with regards to manufacturing locations and what you can and can’t use for regulatory purposes depending on country of manufacture.

ISO E is another synthetic ingredient now widely used by fragrance houses, it acts more like a generic booster for overall fragrance performance versus just a skin longevity agent and again it’s use will be dependent on international location of manufacture. So for Creed, yer batches prior to 2023 are allegedly the ones to go for with certain years since 2010 regarded as vintage. Batch codes usually have the year of manufacture as first double digit although e.g. 2021 is 11Z01 which is a notable batch owing to its more pronounced pineapple top note, 19S01 also memorable as is 19U01 which is smokier allegedly. Having worked with natural ingredients extensively in my time, their only consistency is their variability so you will get inherent batch to batch variation.

As I said, a bit of a rabbit hole…:)