GFF / Pitera / Yeast Ferment Filtrate
The filtered liquid left after culturing the yeast Galactomyces — the fermentation active popularised by Japanese essences. The filtrate is a complex mix of amino acids, organic acids, vitamins and other small fermentation by-products rather than a single defined molecule, which is both its appeal and the reason its effects are hard to standardise. Reported benefits centre on a brighter, smoother, more even-looking surface; the evidence is more cosmetic-grade than the clinical trials behind retinoids or vitamin C.
Galactomyces filtrate isn't dosed as a defined active percentage — in an essence it's usually the base, often the first ingredient, so the headline is closer to 'most of the formula' than to a measured dose. There's no agreed standard between brands, so the fermentation strain, conditions and quality matter more than any number on the label.
Use as an essence after cleansing and before serums, AM and/or PM, patting a thin layer onto damp skin. Generally well tolerated, but ferment filtrates are a known sensitiser for a minority — patch test first if your skin is reactive. It pairs comfortably with niacinamide and hyaluronic acid.
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