(Poly)Saccharides in cosmetic products – From alginate to xanthan gum

he prefix “poly” makes us think of synthetics which are formed by polymerization of smaller units (monomers). As a matter of fact, polysaccharides are biopolymers composed of differently linked single sugar molecules. As a result the characteristics of the sugars completely change. The best known monomer sugars (monosaccharides) are glucose (dextrose, grape sugar), fructose and galactose. Monosaccharides are watersoluble and have a sweet taste with a few exceptions though. The same applies for oligosaccharides i.e. compounds consisting of two or more monosaccharides like e.g. saccharose (sucrose, cane sugar), lactose (milk sugar) and maltose (malt sugar). Saccharose is build up by glucose and fructose, lactose consists of glucose and galactose, and maltose is composed by 2 glucose units. Polysaccharides like cellulose (glucose chains) and chitin (see below) have no specific flavor and are water-insoluble. There are others that only swell like e.g. starch (linear or branched glucose chains). As polysaccharides are inexpensive and easily available due to their natural sources, they have been used in cosmetics for a long time already. Alginates, pectins and xanthan gum represent many others that are not mentioned at this point. In addition, chemical industry has modified and customized the natural substances and has generated refined raw materials with new characteristics. The following substances are used in skin care products: