TRESemmé Collagen+ Fullness System, infused with COLLAGEN has been created with GLYCERINE to penetrate inside the hair. The system works to plump each strand and instantly helps hair look thicker! How to use After shampooing, follow with Collagen + Fullness Conditioner to help you style your hair more easily. Squeeze a generous amount of conditioner onto the palm of your hand and distribute evenly from root to tip. Apply to damp hair focusing on mid-lengths and ends first. Leave-in for 2-3 minutes, then rinse thoroughly.