Leave-in formula represents a characteristic of a cosmetic product, most commonly intended for hair care, indicating that the product is not rinsed out after application. Unlike traditional conditioners or masks that require rinsing, leave-in products remain on the hair and continue to work until the next wash. Their purpose is to provide additional hydration, protection from heat and environmental factors, make detangling easier and reduce static.
Leave-in formulas can come in the form of sprays, creams, serums, or lightweight lotions and are chosen according to hair type and needs. They are especially suitable for damaged, dry, or curly hair, as they provide extended care without weighing the strands down.