Can we go down a preservative free route?

As the name suggests, preservatives keep our beauty products fresh - once opened, bacteria are kept at bay. By way of definition, a preservative is a substance used protect against decay. In cosmetics they prevent certain chemical reactions (such as oxidation) or microbiological changes. They also ensure that an unopened product will remain fresh for between 2 to 3 years. However, even if a treatment contains preservatives, once opened it's shelf life is reduced to a year. 

100% preservative free cosmetics don't exist. Even if you use certified natural, organic products, you'll find preservatives in one form or another, not least because natural ingredients tend to quickly decay. There are loads of different preservatives, some of which are no longer routinely used due to health risks.  

All cosmetic products need to be microbiologically stable. In other words, once opened products need to be protected from bacteria, yeasts and moulds that can cause allergies if they come into contact with the epidermis. The problem is that harmful microorganisms need water to live: as most cosmetic treatments contain water, it's essential that some form of preservative is included in their formulae. Without a preservative, these treatments would only last a few days.  

The golden rule?

Wash your hands before using a treatment, particularly if it comes in a pot into which you'll dab your fingers and, potentially, increase bacterial growth. Cosmetics stored away from heat, light and damp generally last 30 months before opening and between 6 to 12 months once opened. Keeping an eye on use by or best before dates is essential if you want to use a treatment whilst it's still fresh.

Finally, if the colour or smell of one of your treatments changes, the best thing you can do is bin it - out of date products can be harmful and the idea is to pamper not poison our skin!