Smoothing and Shine: Hair serums are often used to add shine and smoothness to the hair, making it look healthier and more polished. Frizz Control: Many serums contain ingredients that help control frizz, especially in humid conditions, leaving the hair more manageable. Vitamins and Nutrients: Some serums include vitamins, antioxidants, and other nourishing ingredients to promote overall hair health. Usage: Hair serums are typically applied to damp or dry hair. Amount: A small amount is usually sufficient, as using too much may make the hair look greasy.