Nioxin Density Defend Hair Thickening Gel is a volumising styling gel designed to create the appearance of fuller, thicker hair. This gel adds body and definition, making hair look voluminous and more substantial. It provides a flexible hold for natural movement and leaves hair feeling soft without stickiness or stiffness. Suitable for all hair types, it can be used daily to enhance your hair styling routine. Nioxin is the #1 Professional brand for thicker, fuller hair, built on a legacy of clinically proven solutions that turn scalp science into true scalp care and hair thickening products. Everyone deserves to grow thicker, fuller hair they can see and feel. Nioxin Grows Results. Caution: Do not get into the eyes. Keep out of reach of children. For any questions or concerns about side effects, always consult a medical professional.