Alternative Preservatives in Cosmetics
Last time on the podcast, we talked about EU's list of approved preservatives and their limits. Today, we're talking about the preservatives that aren't on the list.
There are a great number of these and they range from the nefarious grapefruit seed extract, which we'll talk about first to the new class of bioferment ingredients typically marketed as probiotics which are actually preservatives.
Grapefruit Seed Extract, natural preservative, actually adulterated
Years ago, grapefruit seed extract aka GSE was marketed as a natural preservative. Turns out, it has no preservative efficacy on its own and the GSE that exhibited antimicrobial properties was actually adulterated with some pretty wicked preservatives including parabens and benzethonium chloride and benzalkonium chloride.
Benzalkonium chloride and benzethonium chloride are both limited under EU Annex V to 0.1%.
GSE has also found to be contaminated with parabens and salicylic acid.
Salicylic Acid as the active compound in natural preservatives
I'm not necessarily a hater of salicylic acid, the problem with it is that it encourages cellular turnover because it is a beta hydroxy acid, and when protecting your skin is of primary importance, salicylic acid kind of works against that by promoting cellular turnover and specifically doing that in a way that is contradictory to your body's own processes for cellular turnover.
Your skin naturally produces enzymes that are most active at a pH of around physiologic pH to promote desquamation, and salicylic acid along with other BHAs and AHAs are much lower than your skin's natural pH, and so they interfere with your body's own desquamation process.
Salicylic acid is why ingredients like willow bark extract and radish root ferment filtrate work as preservatives.
One important note: while I don't recommend products containing salicylic acid for your routine skincare, these products are great for haircare, and the reason for this is because your hair strand requires a low pH to keep that cuticle laying flat.
Ferments as preservatives (marketed as probiotics)
Radish Root Ferment (not a fan)
A variety of ferments including radish root ferment and lactobacillus ferment are marketed as probiotics when in fact they're serving a preservative role in the formula.
This is kind of like saying penicillin is a probiotic because it's made by a mold. Penicillin is in fact an antibiotic, and so are the metabolic byproducts made by the lactobacillus bacteria and whatever yeast/mold/bacteria are growing in that radish ferment.
For these ferments, it's not actually that the bacteria or the yeast are being added into your skincare product.
It's that the metabolic byproducts of the yeast or bacteria are isolated from the bacteria/yeast and added to your skincare products. What are these metabolic byproducts? To be honest, this along with the GSE scandal is why I shunned this class of preservatives for years.
One of the compounds made by radish ferment is ninhydrin, which is used in forensics testing to pick up fingerprints. Ninhydrin reacts with the amine in amino acid residues, and just doesn't seem like a great ingredient to use in skincare, so for that reason, Rain Organica doesn't use radish root ferment.
Well, that's one of two reasons Rain Organica doesn't use radish root ferment. The ferment also contains around 20% salicylic acid, which again, is something I don't recommend for routine use in your skincare. Ideally, you want to support your body in its natural processes, not act against those processes.
The other compound in radish root ferment that allows it to act as a preservative is bacteriocins. This is a class of compounds rather than a single compound. Structurally, bacteriocins are either peptide chains (short chain amino acids) or proteins (long amino acid chains with secondary and tertiary structures)
Lactobacillus ferment (currently sold on this one)
References
https://cir-safety.org/sites/default/files/Radish.pdf Radish Root Ferment CIR report
Annex V of Cosmetics Regulation (EC) No 1223/2009. List of Approved Preservatives in Cosmetics.
Annex II of Cosmetics Regulation (EC) No 1223/2009. Substances prohibited from use in cosmetics.
About the Author
Brandy's a formulation scientist and self-proclaimed health geek who loves hiking, gardening, bird-watching, and body boarding.
Her struggle with acne during her teens and 20s led to a holistic and healthy approach to skincare, embracing skin as an organ to be loved and cared for rather than a canvas to wage war on.
Since 2008, she's been developing all-in-one products for a simple routine at home, & Rain Organica started when her backpacking friends asked for a portable skincare routine to keep their skin healthy & happy on and off the trails.
You can try Rain Organica for yourself with The Essentials Kit, a complete skincare routine in just 3 steps.
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