What is the primary function of a hair serum?

The primary function of a hair serum is to add shine and control frizz. Hair serums are typically formulated with silicone and other conditioning agents that coat the hair shaft, providing a smooth finish and enhancing the hair's natural luster. This smoothing action not only creates a glossy appearance but also helps to tame unruly hair strands, making them easier to manage and style.

Moreover, hair serums can create a protective barrier against environmental factors like humidity, which is often the cause of frizz. By sealing the cuticle of the hair, serums help to maintain hydration and prevent moisture from affecting the hair's texture, allowing for a sleek and polished look. This makes them especially popular for individuals with curly or wavy hair textures that are prone to frizz and loss of shine.

While other options touch on different aspects of hair care, they do not encompass the primary function of serums. Some products may indeed assist in specific areas like promoting hair growth or repairing split ends, but these functions are not the main purpose of a serum designed specifically for enhancing shine and controlling frizz.