Legal stuff can be quite complicated, however the cosmetics period after opening has a great purpose, which if known and used, it helps you to protect your eyes and health.
The Cosmetics Period After Opening (or PAO for the cosmetics junkies) was introduced for cosmetics having a shelf life over 30 months because without a sell by date people were ending up using beauty products, especially colour cosmetics, forever and ever. So the cosmetic period after opening tells us how many months you are meant to use a product after opening it. It could be 3, 6, 12 months and so on.
I must confess I have a bright red lipstick that is over 5 years old, still very bright and with no funny smell.
It is not illegal to use an old lipstick, however if the lipstick is contaminated with some bacteria and you happen to have a cracked lip it can cause an infection. You might say so what! well imagine if instead of a lipstick we were talking about a mascara. Every time we apply mascara on our eye lashes, we also apply bacteria to the brush. Being water based the mascara can provide a nice environment for bacteria to grow and prosper in it.
Luckily mascara formulations contain antimicrobial ingredients, guardians that keep bacteria at bay by killing them. However like all killers, they come to an end and stop killing. When this moment comes, the new bacteria introduced can grow and prosper and spread on your eye lashes and eyes 🙁
Our beautiful eyes are not as resilient as our lips, in fact depending on what bacteria we are considering, the eyes can get infected even to the point of permanent blindness if left untreated. The bacterial count to cause an eye infection is only a few hundreds whereas the amount needed to develop a detectable smell by your nose is several millions, when it is far too late.
Given the hazard and the lack of opportunity for early contamination detection it is important to pay attention to the PAO symbol especially for eye products such as mascara and eye liner. If it is too much bother you can simply replace your mascara and eye liner every 3 to 6 months on a regular basis. If you wear contact lenses 3 months is a better option.