What is the primary purpose of using a top coat in nail care?

The primary purpose of using a top coat in nail care is to seal and protect the underlying polish. A top coat creates a protective layer over the colored polish, which helps prevent chipping, fading, and wear. It adds durability to the manicure, allowing it to last longer and maintain its fresh appearance. Additionally, a top coat often provides a glossy finish, enhancing the overall look of the nails.

While some other choices may have relevance in specific contexts, they do not capture the main function of a top coat as effectively. For instance, changing nail color refers to the application of colored polish itself, while helping with drying time is not a primary function of most top coats. Some might thicken the appearance of the nails, but this is not a key purpose of using a top coat in the context of nail care.