Glucomannan Best Humectant Hydration Glucomannan description Glucomannan is prebiotic sugar that combines the simples sugars mannose with glucose. It's derived from the root of the konjac plant, and is a good source of hydrating polysaccharides for skin. As a prebiotic, glucomannan serves as a food source for the probiotics that make up each person's skin microbiome. By supplying food (energy) to your skin's probiotic strains, prebiotics like glucomannan play an important role in keeping skin's microbiome balanced, which translates to healthier-looking skin. In vitro research has shown glucomannan works with a wide range of probiotics to help control the proliferation of blemish-causing bacteria on skin. It also has antioxidant ability, which isn't too surprising given glucomannan comes from a plant. Glucomannan is also a food ingredient, such as konjac flour. Research has documented its contribution to health benefits, such as weight management and controlling glucose levels in the body.