Provide THINNING HAIR WITH DEFINITION AND HOLD with Nioxin 3D Styling Thickening Gel As a part of the Nioxin professional hair styling products line, this hair styling gel gives a noticeable volume boost and a fuller end look. Nioxin THICKEINING HAIR GEL provides strong hold and texture for FULLER-LOOKING and SMOOTH-FEELING HAIR, without stiffness or stickiness.