NIOXIN’s hair loss serum is a leave-on formula that creates a thicker illusion after just one use. It helps to improve the appearance of hair loss after eight weeks, fortifying your stands for a healthier-looking end result. Easy to use, the lightweight, transparent liquid can be sprayed over your locks to target the roots. Hair will seem stronger over time, lowering your risk of breakage when brushing your strands. Dermatologically tested.