Ferments and biotech ingredients

Why fermentation is used

Fermentation does three things that matter cosmetically. It breaks large molecules into smaller ones, which can improve penetration. It generates metabolites - organic acids, peptides, polysaccharides, vitamins - that were not in the starting material. And it can remove or transform unwanted components. So a ferment filtrate is genuinely a different material from its substrate, not a marketing relabel.

The difficulty is that "ferment filtrate" describes a process, not a composition. Two products using the same INCI name may contain materially different things depending on strain, substrate and conditions, and this is rarely disclosed.

The ferments in this range

Rhodotorula ferment filtrate (Vegalab AquaCell) - a yeast ferment, used for hydration and barrier support.

Black truffle ferment filtrate (Bright Micro-Bubble Cleanser), sourced from Southern France - distinctive, and the kind of ingredient where provenance is part of the proposition.

Saccharomyces ferment (Youlief Setup Toner and Setup Cream, 1 ppm) and yeast ferment (Cica Retinal Ampoule) - brewer's and baker's yeast ferments, the most conventional of the group.

Pseudoalteromonas ferment extract (Youlief ECW Ampoule, 249 ppm) - a marine bacterial ferment producing exopolysaccharides, studied for hydration and anti-inflammatory activity. At 249 ppm this is the one present at a plausible level.

Lactic-acid-bacteria ferment (Lumina Brightening Serum), beer yeast at 20% (NanoDensity line) and yeast or millet ferment filtrate (Comfort Cleansing Milk) complete the set.

Glycolipids in the Youlief cleansing serums at 1% are biosurfactants of fermentation origin - a genuinely useful category, being mild and microbiome-compatible relative to conventional surfactants.

Reading a ferment claim

Ask which organism, on what substrate, and what the filtrate is standardised to. A ferment with a named strain and a characterised marker compound is a different proposition from one identified only by genus. Also note the level: several ferments here are at 1 ppm, which is a label presence.

What does ferments and biotech ingredients not do?

Fermentation does not make an ingredient inherently more effective, more natural or better tolerated - some ferment metabolites are irritants. And a ferment is not a probiotic: there are no live organisms in a preserved cosmetic, so claims implying live culture activity are wrong.