What purpose does a toner serve in skin care?

A toner primarily serves to balance the skin's pH levels. After cleansing, the skin's natural pH can become disrupted, especially if the cleanser is alkaline. Using a toner helps to restore the skin to its optimal pH, which is generally around 4.5 to 5.5 for healthy skin. This balance is essential because an appropriate pH level can enhance the skin's barrier function, making it more resilient against environmental factors and reducing the potential for irritation and discomfort.

While toners may have additional benefits such as providing hydration or assisting in preparing the skin for serums and moisturizers, their fundamental role is to help restore pH balance, which is critical for overall skin health. This attribute differentiates toners from other skincare products such as cleansers, which are focused on removing dirt and impurities, or moisturizers that primarily provide hydration to the skin.