Combat ageing, naturally, with the powerful ECO. Vitamin C Serum. The ECO. C Serum is a powerful Vitamin C serum, rich in antioxidants and natural anti-ageing ingredients to revitalise and renew skin. Rosehip, milk thistle and sea-buckthorn are included in the nourishing C Serum to help reduce pigmentation and redness, while boosting elasticity, hydration and cell rejuvenation, leaving the skin more even-toned, smoother and glowing.