Tonic, or toner, comes in different forms, with different functions. They can be clear liquid, milky or even a mist – they work to boost hydration or sometimes acts as a mild exfoliant. You can apply with a cotton pad, but we recommend using your hands to work the product into the skin. Often a forgotten step in a routine, a toner can be a quick way to rehydrate and refresh the skin, before or in place of moisturiser.