Matrix Biolage Deep Smoothing Serum: Intense frizz control, heat and humidity protection for smooth, glossy shine without the weight. The serum delivers all over weightless smoothing and glossy shine with heat styling and humidity protection. So uniquely advanced, it leaves hair feeling light and clean yet totally under control. Smoothes frizzy, unruly, medium to coarse hair with the silky serum of Camellia flower seed to continuously control frizz in hot, humid seasons while replenishing hair's moisture during dry cool seasons. Hair stays naturally smooth, year round, even in up to 97% humidity