Why Do You Need Preservatives in Skincare?

I had a customer ask me this week for skincare products without preservatives. While we were chatting, it became clear to me that she didn't really understand why we needed preservatives. And why would you? We're not cosmetic chemists, we're busy people just trying to choose the safest products we can. So to help you out, I thought I'd whip up a quick blog post on what preservatives are actually for.

You don't have to look very far to find skincare products that contain water. Water is used as a solvent (to dissolve ingredients in) and also to help form emulsions where the oil and water parts of the product turn into creams and lotions. Water is pretty awesome, but anything with water in it is prone to getting bacteria, yeast and mould growing in it.

It's not just water, either. Any product you see with floral waters or hydrosols, aloe vera, and goats milk will all have similar issues. And that counts even if your product doesn't have water in it, but is likely to get water in it, like scrubs that you'll use in the shower. If manufacturers didn't use preservatives, your skin care products would be subject to mould, bacteria and fungus growing in them and making them harmful to use. Even using the wrong preservatives can be a problem.

Without preservatives in skincare and cosmetics, both your standard and natural products wouldn't last a week. It's one of the reasons why you need to be careful making DIY skincare and cosmetics at home. If you're not using the right preservatives, you could be exposing yourself to all sorts of nasties. Even when you're using products with preservatives in, you still need to make sure that you're replacing them regularly. Mascara is a prime example of this. One study found staph bacteria growing in over 35% of mascara tubes after just three months of use. Another study found both staph bacteria and Pseudomonas aeruginosa. Both of these can cause skin rashes and eye infections.

Not all skincare products need a preservative, just the water based ones. Anhydrous products don't need a preservative. Those are products without water or water based ingredients - things like balms, butters and oils. These oil based products use antioxidants like tocopherol (vitamin E), grapefruit seed extract or rosemary oil extract can help to extend the shelf life of oil-based products by preventing rancidity. They don't inhibit the growth of bacteria, yeast or mould like a true preservative would, so these aren't suitable for water based products.

Solid bar soaps don't need a preservative, and liquid castile soaps generally don't need a preservative as the pH level is too high to allow for bacterial growth. Some preservatives are what are considered broad spectrum preservatives, which means that they protect against yeast, bacteria and fungi. Some preservatives are aimed at one alone, and these are usually used with other preservatives to protect against all three. To find out which preservatives you should avoid and which ones are okay, have a look at this article on preservatives that I wrote last year.