There are many skincare ingredients that are considered to be the most important. Some of them include glycerin, lactic acid, and retinol. Glycerin is a moisturizer that is used to keep the skin hydrated. Lactic acid is a natural exfoliator that helps remove dead skin cells from the outer layer of the epidermis. Retinol is vitamin A that helps reduce wrinkles and acne scars as well as helps prevent sun damage.