Fructooligosaccharides (FOS) are a type of oligosaccharides and carbohydrates used in skin care for their moisturizing, prebiotic and potential antioxidant properties. They are composed of short chains of 3-10 fructose units.
They occur naturally in plants and are often found in garlic, sugar beet, chicory, onion and banana, among other fruits and vegetables. Although natural, fructooligosaccharides can also be produced synthetically via fermentation for use in cosmetics.
As a humectant, this ingredient helps promote skin's moisture retention for a supple feel. It further nourishes and supports a healthy skin microbiome through its prebiotic properties. Prebiotics are the food source for probiotics, the "good" bacteria that help the body and the skin's surface maintain microbial balance.
Recent studies also describe the potential antioxidant activity of fructooligosaccharides. This group of ingredients is safe for use in cosmetics without concentration restrictions. https://www.paulaschoice.com/ingredient-dictionary/ingredient-fructooligosaccharides.html?q=Fructooligosaccharides&fdid=ingredients