Hair that need help with moisture and volume may benefit the most from a leave-in conditioner. With Boots Expert Healthy Hair Leave In Thickening Conditioner, you can prevent a flat hair look. The leave-in conditioner has a lightweight formula that helps add definition and volume to your hair. It has moisture-enhancing properties that hydrate the strands and boost their thickness. It detangles the knots and curls in hair, making them smooth to touch and easy to comb. It keeps your hair hydrated, soft and shiny all day long.