C-Tetra®
Close-up profile of a model with glowing skin and closed eyes against a warm gradient background. Text highlights proven, effective & stabilised Vitamin C, maximum results with minimal irritation, and textures to suit every skin type.
Close-up of a model with glowing skin gently touching her cheek against a warm gradient background. Text highlights that 87% of sensitive skins agree this is the most gentle vitamin C serum they have ever used, proven via an independent consumer study.
C-Tetra®
C-Tetra®
C-Tetra®
C-Tetra®
C-Tetra®
C-Tetra®
C-Tetra®
Close-up profile of a model with glowing skin and closed eyes against a warm gradient background. Text highlights proven, effective & stabilised Vitamin C, maximum results with minimal irritation, and textures to suit every skin type.
Close-up of a model with glowing skin gently touching her cheek against a warm gradient background. Text highlights that 87% of sensitive skins agree this is the most gentle vitamin C serum they have ever used, proven via an independent consumer study.
C-Tetra®
C-Tetra®
C-Tetra®
C-Tetra®
C-Tetra®
C-Tetra®
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Dullness

C-Tetra®

  • Brighten
  • |
  • Even
  • |
  • Smooth
Lipid 7% Vitamin C Radiance Serum
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.

*Proven via independent consumer study conducted over 4 weeks on 52 participants with sensitive skin.

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Reasons to shop Medik8

Fast & Tracked Shipping
15% off your first order
All taxes, custom fees and import duties included
Advanced Day Ultimate Protect™
Advanced Day Ultimate Protect™
  • Protect
  • |
  • Repair
  • |
  • Hydrate
 Age-Defying Moisturiser with Photolyase SPF 50+ | PA++++
Key Benefits
Increased Skin Youthfulness

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

Lightweight Nourishment

This jojoba (pronounced 'huh-hoh-ba') seed oil-based formula delivers effective yet non-greasy nourishment for visibly softer and comforted skin.

Brighter, More Even Complexion

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

Proven Results
After
After
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.
How to Use

First-time use

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.

STEP 1

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.

Uses Per Tube

200

Key Ingredients
3% 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.

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 retinol for optimum visible results.

Full List of Ingredients
C-Tetra®
Lipid 7% Vitamin C Radiance Serum
*Although we try our best to ensure this list of ingredients is accurate there may be product upgrades from time to time, or slight variants between different regions based on local laws, meaning the only definitive ingredient list is that which is printed on the product packaging.
  • No artificial fragrance
  • No synthetic colours
  • Paraben free
  • Certified by the vegan society
Experts Recommended

Ultra-gentle & perfect for visibly radiant skin

DANIEL ISAACS
Chief Product Officer

I like everything that Medik8 does and this is no exception.

EVE CAMERON
Beauty Director - Red

The Vitamin C Serum Range

C-Tetra®
Morning
C-Tetra®
(30ml) | $53
Texture

Lightweight Oil

Skin Types

Sensitive Skin

Key Ingredients
  • 7% Tetrahexyldecyl Ascorbate
  • Vitamin E
Benefits
  • Brightening
  • Skin Nourishment
C-Tetra® Luxe
Morning
C-Tetra® Luxe
(30ml) | $70
Texture

Rich Oil

Skin Types

Dry Skin

Key Ingredients
  • 14% Tetrahexyldecyl Ascorbate
  • Squalane
  • Maracuja Oil
Benefits
  • Brightening
  • Youth Boosting
  • Skin Nourishment
  • Dark Spot Reduction
C-Tetra® Advanced
Morning
C-Tetra® Advanced
(30ML) | $78
Texture

Lightweight Gel-Serum

Skin Types

All skin types, especially oily & combination

Key Ingredients
  • 20% Tetrahexyldecyl Ascorbate
  • Phyto Exosomes 
  • Acetyl Zingerone
Benefits
  • Brightening 
  • Age Defense
  • Skin Nourishment
  • Dark Spot Reduction
  • Smooth & Even Complexion

Complete Your Regime

Reviews

Frequently Asked Questions

What's the difference between C-Tetra and C-Tetra Luxe?
C-Tetra is our original, best-selling vitamin C serum. It's the perfect option for those who are new to vitamin C or those with sensitive skin, who still want visible age-defying results. C-Tetra Luxe is our supercharged vitamin C serum - ideal for those looking for clinical brightening and nourishing power. Both serums are formulated with stabilised tetrahexyldecyl ascorbate.
Can I use C-Tetra alongside vitamin A?
Absolutely. In fact we recommend it as part of our pioneering CSA Philosophy which champions vitamin C plus sunscreen by day, vitamin A by night as the simple secret to glowing, youthful-looking skin.
Can I use C-Tetra if I'm pregnant or breastfeeding?
As a cosmetics company, we are unable to provide product advice in relation to medical conditions such as pregnancy. We would 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 to avoid during pregnancy, unless advised by your doctor.
C-Tetra®
(30ml)
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