This groundbreaking serum redefined the standard of how Vitamin C serums should look, feel and perform––which is why it’s earned a cult following from almost every beauty editor in the industry. This water-based serum is bottled in a 100% oxygen-free and light-free environment, capturing Vitamin C in its absolute purest natural form. Read below to see why this clinical-grade, super-effective serum does not need foul-smelling ferulic acid or a concentration of Vitamin C that's higher than 10%. Most clients see visible improvements in 14 days. Therapeutic active: 10% L-ascorbic acid, pH 3.46