Hair serums are specialized hair products that are designed to nourish, protect, and improve the appearance of hair. They are typically lightweight and formulated with a variety of beneficial ingredients, such as vitamins, oils, and proteins, that can help to smooth frizz, add shine, and strengthen hair from the inside out. Hair serums can be applied to damp or dry hair, depending on the product, and are often used as a finishing touch to a styling routine. They can be a great addition to anyone's hair care routine, particularly for those with dry, damaged, or frizzy hair.