Lactose Good Humectant Hydration Lactose at a glance Principal sugar found in milk Acts as a humectant in skin care products Ruled safe as used in cosmetics White or slightly yellow powder in its raw form Animal-derived, so not considered vegan Lactose description Lactose is a disaccharide (sugar made of two molecules) and the principal sugar found in milk. When ingested, it serves as an energy source with a low glycemic index. It also aids in calcium absorption, though after infancy in humans, it becomes more difficult to metabolize, resulting in lactose intolerance for many people. Applied topically, as with other sugars, lactose serves as a humectant, a type of ingredient that attracts water to skin, giving it a plump, dewy look. Humectants serve as building block ingredients for most moisturizers. The independent Cosmetic Ingredient Review Board has ruled lactose safe to use, with no instances of irritation or sensitization, in amounts up to 2.48%. In its raw form, lactose is a white or slightly yellow powder. It’s common to see lactose in a blend with other humectants such as lactic acid and glycerin. Note that because this ingredient is typically animal-derived, it isn’t considered vegan.