Which product is typically used to add moisture to hair?

Leave-in conditioner is specifically designed to add moisture to hair. It acts as a lightweight moisturizer that can penetrate the hair shaft and help maintain hydration throughout the day. This product often contains ingredients such as humectants, oils, and proteins that nourish the hair, improve its manageability, and reduce frizz. Leave-in conditioners can be used on damp or dry hair and provide ongoing hydration without the need for rinsing.

Other products mentioned serve different purposes. Gel is primarily used for styling and providing hold but does not focus on adding moisture. Hair spray is aimed at finishing a hairstyle and ensuring it stays in place, making it less effective for adding moisture. Dry shampoo is intended to absorb excess oil from the scalp and freshen up the hair between washes, but it does not provide any moisture. Therefore, leave-in conditioner stands out as the best choice for adding moisture to hair.