I touched on this in my last blog post - Natural vs “chemical” skincare: an irrelevant debate? In response to the scaremongering around synthetic ingredient often defined as “toxic”, some natural / green beauty products are being sold as “preservative-free”. This either means that the preservatives used haven’t been disclosed, or worse, they’re not using preservatives at all and that is something as consumers we really should be concerned about.
To clarify, I’m not talking about anhydrous (oil only) products that contain no water / will not have any contact with water. For any products that do contain water however, preservatives are critical and they’re one of the most challenging aspects of product formulation. Bear in mind that products that include hydrosols / floral waters, aloe vera, milks etc also need preservatives as these all contain water too. Preservatives prevent the formation of bacteria, yeasts and mould. In fact, with natural products, a preservative becomes even more vital as the usual natural ingredients found in these products (e.g. fruits, botanicals, extracts, clays etc.) are highly nutritive for microbial growth. If you made a skincare product yourself at home you might get away with storing an unpreserved product in the fridge for a few days but certainly no more than a week – it might look or smell ok, but microbes can be invisible to the naked eye. Think about it this way, would you drink milk that has been left out on the counter for a couple of days, or in the fridge for a couple of weeks? There is a huge risk of putting contaminated products on a compromised skin barrier, where penetration of these unwanted microbes is more likely.
Unfortunately, it’s not as simple as just adding a certain percentage of preservative, you need a whole preservation strategy. This includes limiting water content, having an optimal pH that limits microbial growth, minimising ingredients that encourage microbial growth (which unfortunately often means the star ingredients of formulations: fruits, botanicals, milks, honey, hydrosols, aloe vera, extracts, clays), suitable packaging and of course good GMP (Good Manufacturing Practice).
So moisturisers, aqueous serums, toners / mists, non-oil cleansers must contain an effective broad spectrum preservative system alongside a solid preservation strategy. Broad spectrum means it must be effective across a range of gram positive / negative bacteria, yeast and mould. A single preservative is unlikely to offer this as each has its own strengths and weaknesses. So if you’re looking at an ingredients list, you want to see more than just one preservative listed to be sure the product is sufficiently covered. The other advantage of using more than one preservative is that it keeps the level of each individual agent down, minimising irritation and sensitivity. The following ingredients are NOT preservatives and yet are often described as such online (they are in fact antioxidants so very useful in anhydrous products):
- Vitamin E
- Grapefruit seed extract
- Rosemary extract
Furthermore, there are other ingredients that could function as preservatives but would need to be used at such high levels to make them effective that they’d either be unsafe or affect the feel of the product. Examples include: essential oils, glycerin, alcohol, honey, or making a product strongly acidic or alkaline – you won’t want any of this in a high concentration on your skin.
It’s not always safe to assume that just because products are available for sale that they’ve been properly formulated or tested (unless you know this for sure). Unfortunately some sellers aren’t even aware of the need to get products assessed and challenge tested in the EU (this isn’t a requirement in the US). It’s also worth noting that even amongst very well-established brands using effective preservation strategies, microbial contamination can still happen (there were a couple of high profile cases in the last couple of years in the UK).
What should you do?
- Be cautious of “preservative free” claims in natural/ green products (the exception is probably very large, reputable brands where it’s highly unlikely that they could avoid preservative / PET testing and I’d be surprised if they didn’t have a team of expert chemists responsible for formulating their products). If you’re not sure, ask the brand for more details. They should be more than willing to answer your questions and if they aren’t, you have to ask yourself why!
- Check ingredients listings and look for at least a couple of preservatives listed (a Google search will reveal commonly used preservatives in cosmetics)
- Be mindful of expiration dates for your products- this is particularly important for natural products which tend to have a shorter shelf life. Whilst a shorter shelf life is not an issue in itself, don’t be tempted to bulk buy them and have them sitting around for too long, or use them past their expiration date!
- Store your products carefully – keep them in a cool place, with lids tightly screwed on and avoid getting water in them. In the case of jar packaging, use a spatula to minimise contamination
- If you make your own DIY products at home with water or water-containing products like hydrosols etc and you’re not going to finish the product in a few days, you must add a preservative. Bear in mind that most recipes found online for DIY products are unsafe and haven’t been formulated by experts in formulation
- If you have particularly sensitive skin, a compromised skin barrier or you’re immunocompromised, all of the above is even more important for you as your body’s ability to deal with microbes is greatly diminished
