C-Tetra® Advanced

20% Vitamin C Gel-Serum With Phyto Exosomes Full Details

  • Benefits
  • Brighten
  • Even
  • Defend
Medik8 C-Tetra Advanced bottle displayed on a clean white background with translucent serum droplets, highlighting its lightweight gel-serum texture.
Close-up of a woman with radiant, even-toned skin, with text highlighting how C-Tetra Advanced defends against premature ageing by improving brightness, wrinkles, and skin texture.
Before and after close-up of a participant’s skin over 7 days, demonstrating visibly smoother skin texture and refined appearance.
Smiling woman with radiant skin and a swipe of Medik8 C-Tetra Advanced serum on her cheek, emphasising 0% barrier disruption for gentle yet effective brightening.
An infographic titled "Scientifically Proven Reduction in Oxidative Stress*" set against a warm orange background. It compares two microscopic cross-sections of skin (epidermis and dermis). The left image, labeled "SKIN EXPOSED TO ENVIROMENTAL STRESSORS," shows bright yellow glowing areas indicating harmful oxidative stress. The right image, labeled "SKIN EXPOSED TO ENVIROMENTAL STRESSORS WITH C-TETRA ADVANCED," shows significantly darker tissue, demonstrating a reduction in oxidative stress.
Molecular representation of key ingredients in Medik8 C-Tetra Advanced, with text highlighting 20% Vitamin C, Phyto Exosomes, Acetyl Zingerone, Hyaluronic Acid, and N-Acetyl Glucosamine (NAG) for brightening, hydration, and skin barrier support.
Before and after comparison of a participant’s skin over 7 days, showing visibly brighter skin with improved radiance and even tone.
An infographic titled "How To Layer" outlines an AM skincare routine on an orange background. It highlights the "Vitamin C" step featuring C-Tetra Advanced, positioned between "Cleanse" (Surface Radiance Cleanse), "Tone" (Press & Glow), and "Moisturiser & SPF" (Advanced Day Ultimate Protect).
"MEET YOUR VITAMIN C" chart on an orange gradient background with hexagonal graphics. Four Medik8 serums are shown. From left: C-Tetra dropper bottle (7% Vitamin C, for sensitive skins or beginners), C-Tetra Luxe dropper bottle (14% Vitamin C, for dry skin), C-Tetra Advanced pump bottle (20% Vitamin C, for normal, combination, and oily skin), and Super C Ferulic dropper bottle (30% Ethylated L-Ascorbic Acid, for experienced users).
A 30mL amber pump bottle of Medik8 C-Tetra Advanced standing next to its white cardboard carton against a clean white background. Text on the bottle and carton reads "20% Vitamin C Gel-Serum," "Brighten & Age Defence," and "with Phyto Exosomes."
Medik8 C-Tetra Advanced bottle displayed on a clean white background with translucent serum droplets, highlighting its lightweight gel-serum texture.
Close-up of a woman with radiant, even-toned skin, with text highlighting how C-Tetra Advanced defends against premature ageing by improving brightness, wrinkles, and skin texture.
Before and after close-up of a participant’s skin over 7 days, demonstrating visibly smoother skin texture and refined appearance.
Smiling woman with radiant skin and a swipe of Medik8 C-Tetra Advanced serum on her cheek, emphasising 0% barrier disruption for gentle yet effective brightening.
An infographic titled "Scientifically Proven Reduction in Oxidative Stress*" set against a warm orange background. It compares two microscopic cross-sections of skin (epidermis and dermis). The left image, labeled "SKIN EXPOSED TO ENVIROMENTAL STRESSORS," shows bright yellow glowing areas indicating harmful oxidative stress. The right image, labeled "SKIN EXPOSED TO ENVIROMENTAL STRESSORS WITH C-TETRA ADVANCED," shows significantly darker tissue, demonstrating a reduction in oxidative stress.
Molecular representation of key ingredients in Medik8 C-Tetra Advanced, with text highlighting 20% Vitamin C, Phyto Exosomes, Acetyl Zingerone, Hyaluronic Acid, and N-Acetyl Glucosamine (NAG) for brightening, hydration, and skin barrier support.
A video for Medik8 C-Tetra Advanced opens with a close-up of the bottle's label, then shows a woman applying the product to her cheek. A split-screen before-and-after image of a woman's cheek demonstrates how the product can "VISIBLY BRIGHTEN SKIN & REDUCE WRINKLES" after 4 weeks. The video then highlights key ingredients: "20% VITAMIN C" and "PHYTO EXOSOMES" with "0% DISRUPTION TO SKIN BARRIER*". It concludes with a shot of the product alongside the Medik8 logo and a "Certified B Corporation" badge.
A close-up video showing a thick, white, creamy gel-serum texture being swiped across a white surface. Text overlay states "LIGHTWEIGHT & NON-GREASY GEL-SERUM."
Before and after comparison of a participant’s skin over 7 days, showing visibly brighter skin with improved radiance and even tone.
An infographic titled "How To Layer" outlines an AM skincare routine on an orange background. It highlights the "Vitamin C" step featuring C-Tetra Advanced, positioned between "Cleanse" (Surface Radiance Cleanse), "Tone" (Press & Glow), and "Moisturiser & SPF" (Advanced Day Ultimate Protect).
"MEET YOUR VITAMIN C" chart on an orange gradient background with hexagonal graphics. Four Medik8 serums are shown. From left: C-Tetra dropper bottle (7% Vitamin C, for sensitive skins or beginners), C-Tetra Luxe dropper bottle (14% Vitamin C, for dry skin), C-Tetra Advanced pump bottle (20% Vitamin C, for normal, combination, and oily skin), and Super C Ferulic dropper bottle (30% Ethylated L-Ascorbic Acid, for experienced users).
A 30mL amber pump bottle of Medik8 C-Tetra Advanced standing next to its white cardboard carton against a clean white background. Text on the bottle and carton reads "20% Vitamin C Gel-Serum," "Brighten & Age Defence," and "with Phyto Exosomes."

C-Tetra® Advanced

20% Vitamin C Gel-Serum With Phyto Exosomes Full Details

  • Benefits
  • Brighten
  • Even
  • Defend
Not available for purchase

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Suitable For:
  • All skin types
  • Visible signs of ageing
  • Dull or tired-looking skin
How To Use:
  • Apply AM after cleansing
  • Use 2-3 pumps
  • Follow with moisturiser

Reasons to shop Medik8

Free UK Delivery over £25
15% off your first order
'‘No questions asked” easy 30 day returns
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Guide To Layering

Step 1: Cleanse
Item added to bag
£25 / 150ml
Step 2: Tone
Item added to bag
£34 / 200ml
Step 3: Brighten
Item added to bag
£70 / 30ml
Step 4: Protect
Item added to bag
£59 / 50ml

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.

Please Note: Product packaging shown may be different to the product received due to regional variations
C-Tetra® Advanced
KEY BENEFITS
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    Dramatic Skin Brightening

    Clinically proven to visibly brighten skin and even tone in 7 days for a radiant, luminous complexion.[1]

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    Enhanced Skin Barrier Support

    Powerful phyto exosomes deliver replenishing bioactives to skin cells rapidly & effectively, ensuring 0% barrier disruption.[1]

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    Premature Skin Ageing Defence

    Shields skin from damaging free radicals, pollution, and daily environmental stressors to help defend against premature skin ageing.

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    Smooth & Even Complexion

    Clinically proven to visibly improve skin smoothness and texture in 7 days, leaving a soft, polished finish.[1]

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    Lightweight Finish

    The fast-absorbing gel-serum texture hydrates, smooths, and primes, leaving skin instantly refreshed and ready for the day ahead.
PROVEN RESULTS
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  • 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.
HOW TO USE
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how to use Zoom In Icon

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. 

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.
LOVED & RECOMMENDED
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  • Endorsement Icon 1

    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
  • Endorsement Icon 2

    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
  • Endorsement Icon 3

    Love this new product! I have noticed a glow in just a few days and my skin's looking a lot brighter.

    Danielle
    Verified Medik8 Customer
KEY INGREDIENTS
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  • Ingredient Icon 1
    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.

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    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.

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    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.

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    Hyaluronic Acid

    Draws moisture into the skin to instantly plump and deeply hydrate for a soft, supple complexion.

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    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.

  • Full Ingredients
SUSTAINABILITY CLAIMS
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Provenance provides confidence for sustainability claims; helping to prevent ‘green-washing’ and empowering conscious consumers to purchase in line with their values. Provenance ‘Proof Points’ are all third party verified and evidenced through supply chains.
GUIDE TO LAYERING
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C-Tetra® Advanced
Complete Your Regime