Serums

C-Tetra® Advanced

Defend against premature skin ageing and achieve accelerated visible skin brightening. With a next-generation combination of 20% vitamin C and cutting edge phyto exosomes that help shield and improve the skin's recovery from exposure to environmental stressors which can cause premature ageing.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 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. Key Benefits Dramatic Skin Brightening Clinically proven to visibly brighten skin and even tone in 7 days for a radiant, luminous complexion. [1] Premature Skin Ageing Defence Shields skin from damaging free radicals, pollution, and daily environmental stressors to help defend against premature skin ageing. Lightweight Finish The fast-absorbing gel-serum texture hydrates, smooths, and primes, leaving skin instantly refreshed and ready for the day ahead. Enhanced Skin Barrier Support Powerful phyto exosomes deliver replenishing bioactives to skin cells rapidly & effectively, ensuring 0% barrier disruption. [1] Smooth & Even Complexion Clinically proven to visibly improve skin smoothness and texture in 7 days, leaving a soft, polished finish. [1] Proven Results 7 days to visibly brighter skin [1] 7 days to visibly reduced wrinkles [1] 0% barrier disruption [1] 7 days to visibly smoother skin texture [1] 90% reduction of pollution damage to the skin’s surface [2] [1] Proven via independent clinical study conducted over 4 weeks on 32 participants. [2] Proven via in vitro protein carbonylation data against particulate matter pollution on the stratum corneum and epidermis. [3] Proven via in vitro protein carbonylation study using European standard reference environmental pollutants. | Please Note: Product packaging shown may be different to the product received due to regional variations. How to Use First-time use If you're new to C-Tetra Eye, we recommend a patch test at least 24 hours before first use. Learn how to patch test here . How To Use Apply as part of your morning skincare routine. Massage 2-3 pumps across the face, neck and décolletage. Follow with moisturiser and always finish with sunscreen. Uses per bottle 80 Guide to Layering Step 1: Cleanse Surface Radiance Cleanse™ Select a Size Full Size (150ml) Full Size (150ml) Travel Size (40ml) Add to Bag £25 Step 2: Tone Press & Glow® Select a Size Press & Glow™ Press & Glow™ Press & Glow Refill™ Press & Glow (Travel Size - 30ml) Add to Bag £34 Step 3: Brighten C-Tetra® Advanced Full Size (30ml) Add to Bag £72 Step 4: Protect Advanced Day Ultimate Protect™ Full Size (50ml) Add to Bag £59 Key Ingredients 20% Stabilised Vitamin C (Tetrahexyldecyl Ascorbate) A highly potent yet gentle form of vitamin C for dramatic skin brightening and powerful antioxidant protection against premature skin ageing. Phyto Exosomes Encapsulated by nature, our phyto exosomes intelligently deliver proteins, lipids, and messenger molecules to skin cells. Together, alongside our supercharged vitamin C, they help prevent & reduce premature skin ageing by supporting healthier-looking, more resilient skin. Acetyl Zingerone (pronounced ‘a-sea-tul’) A super-antioxidant that works synergistically with vitamin C, enhancing its efficacy while neutralising ageing free radicals and shielding skin from environmental stressors. Hyaluronic Acid Draws moisture into the skin to instantly plump and deeply hydrate for a soft, supple complexion. Acetyl Zingerone (pronounced ‘a-sea-tul’) A super-antioxidant that works synergistically with vitamin C, enhancing its efficacy while neutralising ageing free radicals and shielding skin from environmental stressors. Hyaluronic Acid Draws moisture into the skin to instantly plump and deeply hydrate for a soft, supple complexion. N-Acetyl Glucosamine (NAG) A barrier-supporting, gentle, skin-refiner that smooths the look of pores while helping to increase the skin’s own natural hyaluronic acid levels over time. See More View all Clinically proven Artificial fragrance free Dermatologically tested Proven gentle formula Certified by the vegan society Non-comedogenic Tested on all skin types & tones Experts Recommended "With this kind of Vitamin C percentage, you're going to get maximum brightness to the skin in just 7 days." DR EWOMA UKELEGHE Medical & Cosmetics Doctor & Medik8 Global Ambassador "It’s rare to see such a powerful brightening treatment that also strengthens and supports skin health from within - this does both." DR BIBI GHALAIE Cosmetic Physician & Medik8 Global Ambassador "C-Tetra Advanced combines the potent power of vitamin C with barrier-supporting phyto exosomes alongside superantioxidant acetyl zingerone, to protect against premature skin aging. C-Tetra Advanced is scientifically proven to shield against the environmental stressors that cause premature skin aging, reducing damage by up to 78%." [3] DANIEL ISAACS Chief Product Officer & Founding Partner Of Medik8 What strength vitamin C is C-Tetra Advanced? C-Tetra Advanced contains 20% stabilised vitamin C (tetrahexyldecyl ascorbate). Can I use C-Tetra Advanced alongside Crystal Retinal (vitamin A)? Absolutely. We recommend it as part of our pioneering CSA Philosophy Ⓡ which champions vitamin C plus sunscreen by day, and vitamin A by night as the simple secret to glowing, youthful-looking skin. Can I use C-Tetra Advanced if I am pregnant or breastfeeding? As a cosmetics company, we are unable to provide product advice for medical conditions such as pregnancy or breastfeeding. We strongly recommend discussing the ingredients with your GP or midwife before use. As general guidance, this product does not contain any ingredients which we would recommend avoiding during pregnancy unless advised by your doctor. Can I layer C-Tetra Advanced with Liquid Peptides Advanced MP in the morning? Yes, you can. C-Tetra Advanced and Liquid Peptides Advanced MP are both emulsion-based serums however C-Tetra Advanced is slightly thicker in texture. We recommend applying serums in order of thinnest to thickest consistency. Therefore apply Liquid Peptides Advanced MP first and then apply C-Tetra Advanced. Does C-Tetra Advanced contain fragrance/essential oils? C-Tetra Advanced contains a natural, uplifting citrus fragrance derived from grapefruit essential oil. Where do I layer C-Tetra Advanced in my routine? C-Tetra Advanced should be applied in the morning, after cleansing and toning, but before moisturiser and sunscreen. If you are using multiple serums, we recommend applying them in order of thinnest to thickest in texture. Since C-Tetra Advanced is an emulsion, it should be layered on top of water and oil-based serums. This ensures your skin gets the full benefits of each product. Can I use C-Tetra Advanced if I’ve never used vitamin C before? Absolutely. Although C-Tetra Advanced contains a potent 20% vitamin C, it has been formulated using a very gentle form of vitamin C called THDA (Tetrahexyldecyl Ascorbate) that is suitable for all skin types, even if you’re new to vitamin C. Alongside this, it contains many gentle actives such as phyto exosomes, which offer soothing properties to support the skin barrier. C-Tetra Advanced is also proven to be gentle on all skin types in independent clinical and consumer testing. This means anyone can enjoy C-Tetra Advanced without fear of irritation. I think there’s product left in my bottle that I can’t access with the pump. What do I do? As C-Tetra Advanced is a lightweight emulsion, it is a little thicker than water-based serums and therefore may flow more slowly, however, it was designed for use with a pump so it should still dispense with ease. If there is any residue that the pump is not dispensing, you can unscrew the pump and turn the bottle upside down to pour out any remaining product. This should not be required unless you have used up nearly all of the product. Where do I layer C-Tetra Advanced in my routine? C-Tetra Advanced should be applied in the morning, after cleansing and toning, but before moisturiser and sunscreen. If you are using multiple serums, we recommend applying them in order of thinnest to thickest in texture. Since C-Tetra Advanced is an emulsion, it should be layered on top of water and oil-based serums. This ensures your skin gets the full benefits of each product. Can I use C-Tetra Advanced if I’ve never used vitamin C before? Absolutely. Although C-Tetra Advanced contains a potent 20% vitamin C, it has been formulated using a very gentle form of vitamin C called THDA (Tetrahexyldecyl Ascorbate) that is suitable for all skin types, even if you’re new to vitamin C. Alongside this, it contains many gentle actives such as phyto exosomes, which offer soothing properties to support the skin barrier. C-Tetra Advanced is also proven to be gentle on all skin types in independent clinical and consumer testing. This means anyone can enjoy C-Tetra Advanced without fear of irritation. I think there’s product left in my bottle that I can’t access with the pump. What do I do? As C-Tetra Advanced is a lightweight emulsion, it is a little thicker than water-based serums and therefore may flow more slowly, however, it was designed for use with a pump so it should still dispense with ease. If there is any residue that the pump is not dispensing, you can unscrew the pump and turn the bottle upside down to pour out any remaining product. This should not be required unless you have used up nearly all of the product. Help Products About Resources Luciana B. 🇨🇦 Verified Buyer 07/09/26 ABIOLA O. 🇬🇧 Verified Buyer 07/06/26 Olha T. 🇬🇧 Verified Buyer 06/06/26 Jowharah S. 🇺🇸 Verified Buyer 31/05/26 Angelique N. 🇺🇸 Verified Buyer 17/05/26 Funmi O. 🇬🇧 Verified Buyer 14/03/26