Inulin is a polysaccharide (a big sugar molecule) that is produced by many plants and bacteria. Inulin is widely used in food: it is a sweetener and also is a source of soluble fiber.
Inulin is also considered to be a dietary prebiotic (prebiotics are roughly defined as a food source for beneficial bacteria in our bodies). Inulin passes through most of our digestive system and reaches colon intact (it cannot be digested by our enzymes). Because of this, it is available as a food source to the bacteria in our colon and this is how it supports diversity of gut microflora.
Inulin is one of the most studied prebiotics - when it comes to the ingestible ones. There is no research available that inulin applied to the skin topically can improve or support skin microbiome, even though companies produce and market skincare ingredients with inulin For example, a skincare ingredient Biolin (a combination alpha-glucan-oligosaccaride and inulin on the INCI list) is claimed by its manufacturer to support skin’s microbiome, but the available studies do not include adequate control groups.
Overall, inclusion of inulin in skincare is unlikely to make these products any more “prebiotic” (and definitely not “probiotic”), or even “ skin microbiome friendlier” than a typical drugstore moisturizer.
Photo by Michael Schiffer