Nioxin Pro Clinical's Anti Hair Loss Serum is a leave-on scalp treatment, clinically proven to reduce hair loss in only 8 weeks via improved hair anchorage while thickening hair from the 1st use. By 20% on average How to use - Apply 12-15 pumps of hair growth serum on dry or damp hair daily, massaging evenly across the scalp. -Use with 3-Part System Kits & Night Density Rescue. Nioxin Professional Anti-Hair Loss Leave-On Scalp Treatment For Hair Loss, 70ml