Medik 8 C-Tetra is a revolutionary ultra-stable vitamin C serum which helps combat sun-induced damage to the skin, trigger collagen synthesis, increase the skin s elasticity & density as well as improve the skin s texture & brighten the complexion. Designed for both men & women in their mid-20s to 40s. Regular vitamin C is very unstable & many typical vitamin C products are inactive by the time they are used on the skin, in some cases, they have become pro-oxidant & actually generate free radicals! Ground-breaking stability data on C-Tetra guarantees real vitamin C activity & best of all, unlike L-ascorbic acid (regular vitamin C), C-Tetra will not exfoliate or irritate skin. C-Tetra contains 3% Tetrahexyldecyl Ascorbate, the most potent & highly stable derivative of vitamin C available. C-Tetra has been shown to have upto 4 times the potency L-ascorbic acid & other derivatives such as MAP (magnesium ascorbyl phosphate). Directions: In the morning, after cleansing, apply 3-4 drops directly to the skin & blend evenly across the whole facial area, neck & décolleté. Alternatively, place a drop on your finger & massage into the skin. Leave to absorb for 2-3 minutes. Follow with the application of Hydr 8 SPF25 or your preferred SPF hydrator/sunscreen. Ingredients: Simmondsia Chinensis Oil, Cyclopentasiloxane, Cyclohexasiloxane, Tetrahexyldecyl Ascorbate, Tocopherol (d-Alpha).