Medik8's C Tetra Serum is formulated with an increased strength combination of two key antioxidants, this multi-function serum provides an impressive level of protection against free radicals and environmental stressors. This effective antioxidant formula also helps to brighten uneven tone at the surface while significantly stimulating collagen production within the lower layers. With daily application, this serum noticeably repairs visibly sun-damaged and ageing skin to create a more radiant and youthful-looking complexion.