Serums are the best delivery systems for topical ingredients. Being highly concentrated and extremely potent, they can contain 10x more of the active ingredients than skin care creams. Moisturisers or face creams have larger molecules than a serum, and are used to treat mostly the surface level of the skin. Having smaller molecules than a moisturiser, a serum is able to penetrate deeper and add nutrients into the deeper layers of the skin that a moisturiser or cream is unable to reach. Being much finer in texture, serums are more readily absorbed into the skin.