20% Vitamin C Gel-Serum With Phyto Exosomes. Defend against premature skin ageing and achieve accelerated skin brightening with a next-generation combination of 20% vitamin C and skin barrier science. Clinically proven to brighten skin and visibly improve wrinkles in 7 days[1] with 0% barrier disruption[1], C-Tetra Advanced is engineered for high-performance visible brightening, skin smoothing, and daily antioxidant defence. This intelligent ingredient complex combines potent, stabilised 20% vitamin C with restorative phyto exosomes for deep, controlled delivery and omni-antioxidant acetyl zingerone to neutralise the ageing effects of free radicals. The result? A high-performance, age-defying vitamin C serum that works smarter, not harsher.