Nioxin Intensive Therapy Diamax HTX Thicking Xtrafusion Treatment 3.38 oz / 100ml is an innovative approach to the treatment of thinning hair. Diamax is a leave-on treatment that can be used with the Nioxin 3-part systems for thicker, denser-looking hair. NIOXIN Diamax, with a fusion of Niacin amide, Pantheon and Caffeine, is proven to: 1. Increase the diameter of each existing hair strand 2. Penetrate hair and make it fuller and more manageable 3. Strengthen hair resilience against breakage.