Definition: Liquids with active ingredients like vitamins and anti-oxidants that are chemically formulated with smaller molecules so they can penetrate deep into the skin. Serums are designed to penetrate and treat various skin conditions, such as redness, dehydration or lack of firmness. They are usually applied at the end of a facial. They can also be applied before going to bed or before putting on a day moisturizer.
Common Misspellings: serem