Updated: Oct 18, 2022
Companies selling natural products are desperate to find a preservative that can extend the life of their lotions and potions. Leucidal® Liquid has been the most recent attempt to create shelf-stable cosmetics and personal care products that can be considered natural – and safe. It’s made from fermented radish root, so at first blush, it would seem to pass muster.
Contrary to popular perception, preservatives are not a way to keep products “fresh.” Rather, they need to protect against the natural growth of the wide range of molds/mildews, bacteria and yeasts that exist. In an previous post, I wrote about how preservatives are designed to create a toxic environment so that these natural organisms can’t grow and take over the products we use. Broad spectrum preservatives are created to provide levels of toxicity high enough and broad enough to prevent (or kill) anything that could grow in your jars, tubes and bottles. This is important because it means protection against organisms that could result in infections to your skin/body.
If you think about how bacteria and fungi grow in the presence of water, and considering that almost all cosmetics/toiletries are made with water (often as the first ingredient), you would have to question such a claim that one plant extract or derivative could guard against all the strains that thrive in moist, creamy environments. That’s why when Leucidal Liquid came out as a “natural” preservative it seemed too good to be true. Logically speaking, I suspected it might fend off some growth, but it was unlikely to fend off all.
Some researchers in Canada had the same question. An independent study conducted at the University of Alberta, Edmonton, that was published in March 2015 in the Journal of Agricultural and Food Chemistry, tested what would appear on a product label as Leuconostoc/radish root ferment filtrate and is manufactured under the name of Leucidal® Liquid. The researchers found:
“In summary, the antimicrobial activity of commercial Leuconostoc/radish root ferment filtrates (LRRFF) are attributed to salicylic acid and didecyldimethylammonium salts. Moreover, these two compounds are too deficient in 14C to be the product of recent fermentation, suggesting that they are derived from petroleum feedstock. We were unable to detect antimicrobial peptides in any sample of fermented radish root filtrate.”
Aside from salicylic itself being an estrogen mimicker with problems of its own, the researchers also stated that didecyldimethylammonium chloride (a disinfectant that was found to cause infertility and birth defects in mice) has:
"Toxicity to aquatic organisms and can also affect human health. They are known to enhance permeability of salicylic acid through animal skin, and can cause skin allergenic effects, asthma, and lung problems, as well as eye irritation."
Now, on the flip side, when I posted the question about Leucidal to a Facebook group, a representative from a company that supplies Leucidal responded to say that the study is flawed and its assertions misleading. Her biggest criticism, along with others, was that its funding came from Griffith Foods, a competitor, thereby providing an incentive to produce damning results.
It's not as though the financial interests were hidden. Not at all. They are fully and clearly disclosed as part of the study. Maybe I'm naive, but it seemed like appropriate protocol. After all, the inquiry is a legitimate one, and paying for it does not prove a causal relationship to fabricating results. So what is one left to do when you have two competing interests batting about two competing truths?
I have contacted both the corresponding author of the study and the company who funded it and will update as soon as I have more information.
You may also enjoy reading the follow up to this article, More On The Leucidal Liquid Safety Study Debate.