C-Tetra®

Lipid 7% Vitamin C Radiance Serum Full Details

  • Benefits
  • Brighten
  • Even
  • Smooth
Bestseller
A bottle of Medik8 C-Tetra Lipid Vitamin C Radiance Serum open with its dropper resting diagonally across the top. Set against a clean white background, the bottle is surrounded by three clear puddles of serum, showcasing its liquid texture.
Close-up portrait of a woman with her eyes closed, showcasing a bright and even skin tone. Text highlights that the product "Restores the look of skin radiance in 7 days," delivers a visibly brighter tone, and increases skin youthfulness.
Close-up of a woman with a glowing, radiant complexion resting her hand on her cheek. Text states: "87% of sensitive skins agree this is the most gentle vitamin C serum they have ever used." Smaller text below notes results based on a consumer study.
"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).
An infographic titled "HOW TO LAYER" displaying a four-step morning routine: Cleanse (Surface Radiance Cleanse), Tone (Press & Glow), Vitamin C (C-Tetra), and Sunscreen (Advanced Day Total Protect). Expert advice at the bottom suggests pairing with vitamin A at night.
A comparison table titled "FIND YOUR VITAMIN C" featuring six Medik8 products. It lists each product name, its Vitamin C percentage, and its ideal user—ranging from C-Tetra Cream (3% Vitamin C) for beginners to Super C Ferulic (30% Ethylated L-Ascorbic Acid) for experienced users.
An infographic titled "THE CSA PHILOSOPHY" explains a three-step skincare approach: Vitamin C in the morning to brighten, Sunscreen in the morning to protect, and Vitamin A at night to renew. The text claims this addresses 90% of anti-ageing skincare needs.
An amber glass bottle of Medik8 C-Tetra lipid vitamin C radiance serum shown next to its white cardboard carton. Both are set against a clean white background with a subtle shadow.
A bottle of Medik8 C-Tetra Lipid Vitamin C Radiance Serum open with its dropper resting diagonally across the top. Set against a clean white background, the bottle is surrounded by three clear puddles of serum, showcasing its liquid texture.
Close-up portrait of a woman with her eyes closed, showcasing a bright and even skin tone. Text highlights that the product "Restores the look of skin radiance in 7 days," delivers a visibly brighter tone, and increases skin youthfulness.
Close-up of a woman with a glowing, radiant complexion resting her hand on her cheek. Text states: "87% of sensitive skins agree this is the most gentle vitamin C serum they have ever used." Smaller text below notes results based on a consumer study.
A video featuring the Medik8 C-Tetra serum bottle and a woman with glowing skin. Text overlays highlight key benefits: "Restores visible skin radiance in just 7 days," contains 7% Vitamin C, and is ideal for sensitive, congestion-prone skin, or those new to Vitamin C.
"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).
An infographic titled "HOW TO LAYER" displaying a four-step morning routine: Cleanse (Surface Radiance Cleanse), Tone (Press & Glow), Vitamin C (C-Tetra), and Sunscreen (Advanced Day Total Protect). Expert advice at the bottom suggests pairing with vitamin A at night.
A comparison table titled "FIND YOUR VITAMIN C" featuring six Medik8 products. It lists each product name, its Vitamin C percentage, and its ideal user—ranging from C-Tetra Cream (3% Vitamin C) for beginners to Super C Ferulic (30% Ethylated L-Ascorbic Acid) for experienced users.
An infographic titled "THE CSA PHILOSOPHY" explains a three-step skincare approach: Vitamin C in the morning to brighten, Sunscreen in the morning to protect, and Vitamin A at night to renew. The text claims this addresses 90% of anti-ageing skincare needs.
An amber glass bottle of Medik8 C-Tetra lipid vitamin C radiance serum shown next to its white cardboard carton. Both are set against a clean white background with a subtle shadow.

C-Tetra®

Lipid 7% Vitamin C Radiance Serum Full Details

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

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Sustainability Claims Provenance®
Suitable For:
  • All skin types
  • Dull or uneven skin tone
  • Those new to vitamin C
How to Use:
  • Apply AM after cleansing
  • Massage 4 drops over face & neck
  • Follow with sunscreen

Reasons to shop Medik8

Free UK Delivery over £25
15% off your first order
'‘No questions asked” easy 30 day returns
Earn points every time you shop

Guide To Layering

Step 1: Cleanse
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£25 / 150ml
Step 2: Tone
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£35 / 150ml
Step 3: Brighten
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£45 / 30ml
Step 4: Sunscreen
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£59 / 50ml

Restore the look of skin radiance in just 7 days* with cult-favourite C-Tetra.

Formulated with a stabilised form of vitamin C (7%) called tetrahexyldecyl ascorbate (pronounced 'tetra-hexul-deckul as-CORR-bate'), this lightweight serum works to visibly brighten uneven skin tone and reduce the look of fine lines and wrinkles, while remaining gentle on sensitive skin.

Fortified with vitamin E, this antioxidant powerhouse also protects the skin against the ageing and damaging effects of free radicals for a more youthful and healthy-looking complexion overall. The perfect option for those who are new to vitamin C, or those with sensitive skin.
C-Tetra®
KEY BENEFITS
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    Increased Skin Youthfulness

    Proven to simultaneously smooth the look of fine lines and wrinkles while visibly boosting skin glow and radiance.

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    Brighter, More Even Complexion

    Proven to visibly brighten the skin tone, for a more even and healthy-looking skin appearance.

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    Lightweight Nourishment

    This jojoba (pronounced 'huh-hoh-ba') seed oil-based formula delivers effective yet non-greasy nourishment for visibly softer and comforted skin.
PROVEN RESULTS
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  • 7 days to restored skin radiance*
  • 7 days to visibly brighter smoother skin*
  • 96% of sensitive skins agreed C-Tetra was gentle on the skin*
  • 4 weeks to visibly reduced wrinkles & dark spots*
  • 90% agree skin feels instantly softer*

*Proven via independent consumer study conducted over 4 weeks on 52 participants with sensitive skin..accordion-proven-results | Please Note: Product packaging shown may be different to the product received due to regional variations.
HOW TO USE
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STEP 1

If you're new to C-Tetra, we recommend a patch test at least 24 hours before first use. Learn how to patch test here.

After cleansing in the morning, massage 4 drops across the face, neck and décolletage.

STEP 2

Leave to absorb before applying sunscreen. We recommend Advanced Day Ultimate Protect.
LOVED & RECOMMENDED
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  • Endorsement Icon 1

    Softens visible ageing concerns while being tolerable for all.

    BRIDGET MARCH
    Digital Beauty Director - Harper's Bazaar
  • Endorsement Icon 2

    My wrinkles have almost disappeared!

    TATIANA S
    Verified Medik8 Customer
KEY INGREDIENTS
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  • Ingredient Icon 1
    7% Stabilised Vitamin C (tetrahexyldecyl ascorbate)

    A low-irritation form of vitamin C that delivers exceptional antioxidant protection against harmful free radical damage while brightening and supporting collagen production for a visibly even, more youthful-looking complexion.

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    Vitamin E

    A powerful antioxidant that provides additional antioxidant protection against the ageing effects of free radicals. It also helps to boost the power of vitamin C for optimum visible results.

  • 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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FAQS
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C-Tetra®
Complete Your Regime