Probiotics, prebiotics and ferments in cosmetics: what Lactobacillus Ferment and Bifida Ferment Lysate mean
“Probiotic” creams rarely contain living bacteria. What INCI names such as Lactobacillus Ferment, Bifida Ferment Lysate or Galactomyces Ferment Filtrate actually describe, what prebiotics like Inulin do in a formula, and what the label cannot tell you.
Updated: 31 October 2026 · Reviewed by: Kamil Pyziak
The skin microbiome and the marketing around it
The skin is home to a large community of microorganisms – bacteria, yeasts and others – often called the skin microbiome. Research into how this community relates to skin condition has grown quickly, and cosmetics have followed with claims such as “probiotic”, “microbiome-friendly” or “balances the skin flora”.
None of these phrases is a legally defined category in EU cosmetics law. Like all claims, they must be truthful and supported, but their exact meaning depends on the brand. The INCI list is the best way to see what kind of ingredient is actually behind them.
“Probiotic” rarely means alive
In nutrition, probiotics are live microorganisms. Most cosmetics, however, are designed to prevent microbes from growing: water-based products contain preservatives, and a stable cream full of living bacteria would be difficult to reconcile with that. That is why the vast majority of “probiotic” cosmetic ingredients are not living organisms.
Instead, they are products of microorganisms: ferments (what a culture produces during fermentation), lysates (microbial cells that have been broken open) or filtrates (the liquid left after the microorganisms have been removed). Some sources call these non-living ingredients “postbiotics”. Products claiming to contain live cultures exist but are an exception and usually need special formulation.
How to read ferment names
INCI names for these ingredients follow a pattern: the microorganism, sometimes the material it was grown on, then Ferment, often followed by Lysate, Filtrate or Extract. Lactobacillus Ferment and Lactobacillus Ferment Lysate come from lactic acid bacteria. Bifida Ferment Lysate comes from bifidobacteria. Lactococcus Ferment Lysate and Streptococcus Thermophilus Ferment are other bacterial examples.
Yeast and fungal ferments are just as common. Saccharomyces Ferment Filtrate is based on yeast, and Galactomyces Ferment Filtrate – known from many “essence” products – comes from a yeast-like fungus. A name tells you the organism and the type of preparation, but not the strain, the process or the concentration.
Fermented plant extracts
Many ingredients combine a microorganism with a plant: the plant material is fermented and the result is filtered. Names like Lactobacillus/Soybean Ferment Extract or Rice Ferment Filtrate (Sake) follow this logic. Fermentation can change the composition of the starting material, for example by breaking down sugars and proteins into smaller molecules or producing organic acids.
Fermented extracts are especially popular in Korean and Japanese skin care. Whether a fermented version of a plant performs differently from an unfermented one in a cosmetic depends on the specific ingredient; general statements such as “fermentation makes ingredients more effective” cannot be checked on the label.
Prebiotics: food for microbes
In nutrition, prebiotics are substances that feed beneficial microorganisms. In cosmetics the term is used for ingredients said to support a balanced skin flora, typically sugars and sugar chains. Examples are Inulin (often from chicory), Alpha-Glucan Oligosaccharide, Fructooligosaccharides and the sugar complex Xylitylglucoside (often with Anhydroxylitol and Xylitol).
Many of these ingredients are also humectants: they bind water and contribute to the feel of a product. Evidence for their effect on the skin microbiome comes largely from studies by ingredient suppliers, so “prebiotic” is best read as a description of the intended role rather than a proven outcome for every product.
Ferments and preservation
Some ferment filtrates, for example Leuconostoc/Radish Root Ferment Filtrate, are offered by suppliers because of their antimicrobial properties and appear in products marketed as using “natural preservation”. In the EU, however, only substances listed in Annex V of the Cosmetics Regulation may be used as preservatives. Ferments are usually declared with other functions, such as skin conditioning, and products that use them often combine them with other ingredients that help protect the formula.
Whatever the system, a product must pass the manufacturer’s preservation testing to be safe throughout its shelf life. The period-after-opening symbol on the pack still applies.
What the label does not tell you
The INCI name does not reveal the strain of the microorganism, whether any cells are still alive, how the ferment was processed or how much of it a product contains. A ferment near the end of a long list may be present in a very small amount. The label also cannot tell you whether the product has a measurable effect on your skin microbiome.
If you avoid certain raw materials for dietary, religious or ethical reasons, note that some ferments are grown on milk, soy or other substrates that appear in the name only sometimes. For skin conditions such as acne, rosacea or eczema, ask a pharmacist or dermatologist rather than relying on a “probiotic” claim.