I lactobacillus ferments, in the INCI Lactobacillus Ferment o Lactobacillus Ferment Lysate, are obtained by fermenting a substrate with lactobacilli and then releasing the contents of the bacterial cells. They belong to the family of postbiotics, the latest frontier in microbiome skincare.
What ends up in the formula are the metabolites of fermentation: peptides, organic acids, and polysaccharides. On the skin, they help maintain the slightly acidic pH of the acid mantle and support the balance of the microbiome, the ecosystem of microorganisms that lives on the surface and contributes to the barrier function. This is a more robust approach than one based on live organisms: the metabolites are stable over time, compatible with the preservative system, and active from the first day to the last of the product's shelf life.
They are suitable for reactive skin and during periods when the surface balance has been challenged: after exfoliation, sun exposure, or a period of using overly degreasing cleansers. They are used morning and evening, every day.
One clarification that helps when navigating labels: the word “probiotic” on a cosmetic product is not technically correct, because a probiotic is, by definition, a live microorganism, and it cannot be one in a preserved product. Postbiotic accurately describes what the ingredient is and what it does—and that is also why it works reliably.
