A skin serum is a lightweight, topical skincare product that contains a high concentration of active ingredients, such as hyaluronic acid, vitamin C, and retinol. Unlike moisturizers, serums are designed to penetrate the skin quickly and deliver intensive doses of ingredients that can address common skin complaints, such as aging, wrinkles, and dark spots

. They are typically applied to the skin after cleansing and before moisturizing, and they come in various formulas, including gels, oils, and light creams

. Serums are recommended for anyone who is concerned about aging and are considered a key step in a solid skincare routine