Polyglycerin-3 is polymerized glycerin, which is used in cosmetic products to moisturize the skin. Due to its large molecular size, it penetrates the skin relatively slowly, thereby providing long-lasting hydration. It also forms a protective barrier, binds water, and locks it into the upper layers of the skin. It is considered suitable for use in cosmetic products and has been classified as safe as part of a safety assessment of cosmetic ingredients.(1)