This ultra-light, highly concentrated volumizing shampoo for fine hair is clinically proven to strengthen, repair, and prevent future damage from everyday elements, styling, or salon services.* The best shampoo for fine hair has to repair as it volumizes. Nº.4FINE gently removes buildup to leave hair clean and soft with lasting volume, body, and bounce - never weighed down or dried out. *When used with Nº.5FINE Bond Maintenance Conditioner. TEST RESULTS Doubles hair volume instantly and all day /// Doubles hair volume instantly for 8 hours 60% reduction in breakage*t*tested on bleached hair Clinically proven to repair and prevent future damage Clinically proven to strengthen hair USAGE RESTRICTIONS Avoid contact with eyes.