A brown bottle labeled "Medik8 C-Tetra®" with a dropper containing a clear liquid, and several drops of the Vitamin C serum are on the surface below it.

A hand holds a bottle of Medik8 C-Tetra® against an orange background. Text highlights benefits in one week: brighter skin, smoother skin, healthy-looking glow, and restored skin radiance. This potent serum helps fight ageing effectively.

Close-up of a person applying a hydrating serum to their face with a dropper. Text overlay reads: "87% of sensitive skins agree this is the most gentle vitamin C serum they've ever used to fight ageing. C-Tetra® by Medik8.

Two Medik8 products are displayed. The C-Tetra® Luxe on the left claims 2x more vitamin C and improved results, perfect for those looking to fight ageing. The ultra-gentle C-Tetra® on the right is suitable for sensitive skin, offering hydrating serum benefits.

Image of C-Tetra® by Medik8 with text highlighting its benefits: antioxidants for youthful skin, high performance with low irritation, and ultra-lightweight, fast-absorbing, non-greasy formula—an essential in Vitamin C serums to fight ageing effectively.

Two amber glass bottles of Medik8 C-Tetra® Vitamin C serum, one with a dropper, are displayed on an orange surface. The bottle on the right rests on a small orange block, promoting a regimen designed to fight ageing.

A small brown glass bottle labeled "Medik8 C-Tetra®" sits next to a white box with the same name, reportedly containing a Vitamin C serum that fights ageing and boosts radiance.

A 30ml bottle of Medik8 C-Tetra® Vitamin C Radiance Serum, a potent Vitamin C serum designed to fight ageing, is shown next to its packaging box.

Image showcasing Medik8's CSA Philosophy for skincare: using C-Tetra® for brightening, Sunscreen for protection, and Vitamin A for renewal. Each product, including hydrating serums, is recommended for specific times of use: AM or PM to fight ageing effectively.

C-Tetra®

Name: C-Tetra®
Brand: Medik8
SKU: P09576
Price: 1800 EUR
Availability: InStock
Rating: 4.8 (341 reviews)

Lipid Vitamin C Radiance Serum

30ml

€18

C-Tetra®

Buy Now

Free & Fast Delivery in Cyprus with ACS

Medik8’s cult-favourite vitamin C serum, featuring stabilised vitamin C that is gentle on sensitive skins and vitamin C-beginners, yet effective in delivering visible brightening results.

Up to 6 months supply from a full size bottle (2 months' supply from a travel size).

KEY BENEFITS: A proven low- irritation formula, 96% of sensitive skins found C-Tetra to be gentle on their skin.*
RESULTS: Vitamin C minimises the appearance of fine lines and wrinkles over time, while helping to visibly balance and brighten the skin tone.
KEY INGREDIENTS: Tetrahexyldecyl Ascorbate (Vitamin C) & Vitamin E

Key Benefits
- Daily Glow
  The silky jojoba oil-infused serum works to effortlessly give skin a boost of radiance, promoting a visible healthy glow in as little as 7 days.*
- Antioxidant Power
  
  Vitamin C and E provide daily protection from harmful free radicals generated by sun exposure, which can cause premature skin ageing.
- Gentle yet Effective
  Tetrahexyldecyl ascorbate is a stabilised, gentle form of vitamin C which makes it perfect for those new to vitamin C, or sensitive skins that don’t want to compromise on results.
- Looking for more power?
  
  Check out C-Tetra Luxe, with double the concentration of vitamin C as C-Tetra and additional brightening and nourishing ingredients for supercharged results.
  
  ^{*Proven via independent consumer study conducted over 4 weeks on 52 participants with sensitive skin.}
How It Works
Your skin contains natural antioxidants that work to defend against free radicals from the environment. When these environmental free radicals outweigh your skin’s antioxidants, the skin can no longer protect itself. Free radicals latch onto the defenceless skin cells, causing irreparable damage, which ultimately leads to premature skin ageing.
1. C-Tetra works to protect the skin from free radical damage, featuring vitamin C to boost the natural antioxidant defence levels in the skin. Vitamin C is a key pillar of our CSA Philosophy, due to being one of the most powerful vitamins for preventing the signs of premature skin ageing. Vitamin C also helps to stimulate collagen production, and can disrupt the overproduction of melanin to brighten the appearance of dark spots and uneven skin tone. The result? Visibly radiant, healthier, more youthful-looking skin. C-Tetra contains tetrahexyldecyl ascorbate, a form of vitamin C which is a stabilised modification of ascorbic acid (the purest form of vitamin C) that is gentle on the skin yet proven to deliver visible results.
2. Vitamin C and vitamin E work together synergistically as 'network antioxidants', boosting the serum’s overall antioxidant effect to keep skin protected throughout the day.
3. C-Tetra is based on jojoba seed oil, for lightweight nourishment and an instant glowing appearance. The natural emollient oil slips effortlessly into the skin barrier, delivering the vitamin C benefits with ease.
4. Perfect Pair
  When combined, vitamin C and sunscreen give skin the ultimate protection against the sun and environment throughout the day, to minimise signs of premature ageing. Shop our recommended SPF day cream Advanced Day Ultimate Protect here.
How To Use
1. After cleansing in the morning, massage 4 drops across the face, neck and décolletage
2. Leave to absorb before applying sunscreen. We recommend Advanced Day Total Protect.
3. Patch testing prior to use is advised. Refer to medik8.co/patch for an in-depth guide to patch testing.
4. Interested in routines & layering?
  
  C-Tetra features in many of our carefully curated regime guides, including our Fine Lines Defence regime. Click the link for additional product recommendations and easy-to-follow layering advice.
Ingredients
Tetrahexyldecyl Ascorbate
A lipid-soluble form of vitamin C that provides exceptional antioxidant protection from harmful free radicals, while stimulating collagen production for a youthful complexion.

Vitamin E
A lipid-soluble antioxidant that is naturally present in the skin. Vitamin E protects the skin from free radicals and is regenerated by vitamin C for optimum power.

Full Ingredients
- NO ARTIFICIAL FRAGRANCE
- PARABEN FREE
- VEGAN FRIENDLY
- ZIPPER DONATION
- NO SYNTHETIC COLOURS
- NO PHTHALATES
- ALCOHOL FREE
- CRUELTY FREE
Used in Professional Treatments

Boost the results of C-Tetra®

Visit a Medik8 specialist for a detailed skin consultation and experience one of our relaxing anti-ageing facial treatments.

Rewind Professional Skin Peel

A targeted peel that helps to promote collagen production to reduce the appearance of fine lines and wrinkles. It fades away imperfections, leaving the skin visibly smoothed and rejuvenated.

Get a consultation
The Science Behind

“It is exceptionally difficult to formulate a long-lasting vitamin C serum that will keep its power over time. It is notoriously unstable, sensitive to oxidation and can often turn yellow in colour, which indicates that it has gone off. Medik8’s C-Tetra range utilises an extremely stable form of vitamin C, called tetrahexyldecyl ascorbate. This molecule is altered to make it less reactive to oxidation, meaning that even 6 months down the line you can be sure your vitamin C is still as potent as when you first opened it.”

Daniel Isaacs, Medik8 Director of Research

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C-Tetra®

Lipid Vitamin C Radiance Serum

Product Advice from the Experts

Daily Glow

Antioxidant Power

Gentle yet Effective

Looking for more power?

Tetrahexyldecyl Ascorbate

Vitamin E

Boost the results of C-Tetra®

Rewind Professional Skin Peel

Reviews

WHAT WE RECOMMEND WITH THIS...

Surface Radiance Cleanse™

Resurfacing AHA/BHA Mangosteen Cleansing Gel

Advanced Day Total Protect™

Age-Defying Moisturiser SPF 30 | 5* UVA

Crystal Retinal®

Stable Retinal Night Serum Vitamin A