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C-Tetra®

MEDIK8 C-Tetra® 30ml

%0 4.73 | 849 reviews
Box

£42.00 (£1.40 per ml)

In stock

If you like we can let you know when we have some more.

Restore the appearance of skin radiance in just 7 days* with Medik8’s cult favourite C-Tetra serum.

Expertly formulated by their skincare experts with a stabilised form of vitamin C (tetrahexyldecyl ascorbate ), this lightweight serum reduces the appearance of fine lines and wrinkles and visibly brightens uneven skin tone - all while remaining gentle on sensitive skin.

The addition of antioxidant-rich vitamin E protects the skin against the damaging and ageing effects of free radicals for a more healthy, youthful-looking complexion overall. The perfect daily serum for those who are new to vitamin C, or have sensitive skin.
*Proven via independent consumer study conducted over 4 weeks on 52 participants with sensitive skin.

Key Benefits:
Increased Skin Youthfulness
Proven to smooth the appearance of fine lines and wrinkles and visibly boost skin's radiance in 7 days*
*Proven via independent consumer study conducted over 4 weeks on 52 participants with sensitive skin.

Brighter, More Even Complexion
Proven to visibly brighten the skin in 7 days* and reduce the appearance of wrinkles & dark spots in 4 weeks*
*Proven via independent consumer study conducted over 4 weeks on 52 participants with sensitive skin.

Gentle, Lightweight Nourishment
The jojoba seed oil-based formula delivers non-greasy yet effective nourishment for visibly comforted and softer skin.
87% of sensitive skins agree this is the most gentle vitamin C serum they have ever used*
96% of sensitive skins agreed C-Tetra was gentle on the skin*
*Proven via independent consumer study conducted over 4 weeks on 52 participants with sensitive skin.

Proven Results:
7 days to restored skin radiance*
7 days to visibly brighter
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.

Key Ingredients:
Stabilised Vitamin C (tetrahexyldecyl ascorbate)
This stable, low-irritation form of vitamin C is incredibly effective on the skin; delivering exceptional protection against ageing free radicals. Supporting collagen production and brightening the skin tone, it leaves the complexion visibly more even, radiant and youthful-looking.

Vitamin E
Rich in antioxidants, vitamin E helps to protect the skin against ageing free radicals. It also helps to boost the power of vitamin C for maximum visible results.

Good to Know:
NO ARTIFICIAL FRAGRANCE
NO SYNTHETIC COLOURS
PARABEN FREE
CERTIFIED BY THE VEGAN SOCIETY

Directions

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.

How to Layer C-Tetra
AM: Apply C-Tetra after cleansing and toning in your morning skincare routine. Always follow with sunscreen.

Ingredients

Simmondsia Chinensis (Jojoba) Seed Oil, Cyclopentasiloxane, Cyclohexasiloxane, Tetrahexyldecyl Ascorbate, Citrus Grandis (Grapefruit) Peel Oil, Tocopheryl Acetate, PPG-12/SMDI Copolymer, Limonene, Citral, Linalool, Geraniol.

This list of ingredients may be subject to change, please consult the packaging of the product purchased.

+Offer

FREE Hydr8 B5™ 30ml when you spend £90 on Medik8.*

*One free gift per order. Valid until the 27th October or whilst stock lasts. Your free gift will automatically add to the shopping bag page. Total at order summary must be £90 or more worth of Medik8 products, after any Promotion Code, Brands You Love discount and before delivery charges are applied. Cannot be used in conjunction with any other Promotion and this offer is not applicable to previously made or pending purchases. Excludes Gift Voucher, Sephora Favourites Advent Calendar and Fragrance Gift Box purchases. Cannot be used in conjunction with any other Promotion and this offer is not applicable to previously made or pending purchases. This offer is available online at Sephora.co.uk to UK Mainland customers only.

Shop this offer

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Rated 5 out of 5 by from Fantastic product I purchased the travel size of C-Tetra as it was my first time using Vitamin C. I started slowly, applying twice a week, building up to every other day with no issue. The main things I noticed straightaway was how good my skin felt after application and the gentle citrus fragrance is wonderful. It's not greasy in any way, and is absorbed quickly into the skin. I'll start using it daily soon as part of my morning routine; I use Crystal Retinal 3 in the evenings. It's a bit too soon to show any drastic results, but at 54 my skin feels smoother and is the best it has felt for a long time.
Date published: 2025-10-15
Rated 5 out of 5 by from Excellent, not harsh on the Excellent, not harsh on the skin and good size bottle
Date published: 2025-10-12
Rated 5 out of 5 by from Wonderful Love this soothing C Tetra serum. It’s great in the morning and at night under my moisturiser. It’s a great base for make up too. It’s soothing and the perfect remedy for any dryness.
Date published: 2025-10-04
Rated 4 out of 5 by from C - Tetra Vitamin C Serum – I’ve been using this daily as my skin was looking quite dull. After just 4 weeks, I can see a noticeable difference—my skin looks brighter and more even, and my friends have even commented! Highly recommend.
Date published: 2025-10-02
Rated 5 out of 5 by from C-Tetra serum This is the first vitamin C product that my skin has not reacted poorly to, others have made my skin go bright red. I've been using this every day, my skin is brighter and clearer now.
Date published: 2025-10-01
Rated 5 out of 5 by from Excellent product Very pleased with C-Tetra, I’ve been using it for some time and definitely has made my skin look radiant and smoothed fine lines. You only need to apply a couple of drops. My skin is also softer.
Date published: 2025-10-01
Rated 5 out of 5 by from Great Vitamin C Serum Lightweight, absorbs quickly, and makes my skin look brighter and fresher. Perfect for daily use.
Date published: 2025-10-01
Rated 3 out of 5 by from C Tetra made my skin softer but no difference on dark spots I like the feel of C tetra on my skin, it made it smoother and softer but I don’t see any difference on my dark spots at all so a bit disappointing. Guessing I need to switch to a higher concentration.
Date published: 2025-09-29
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Can I use this serum under eyes?

Asked by: Anonymous
Yes absolutely! 
Answered by: Anonymous
Date published: 2023-05-24

What % vitamin c?

Asked by: Anonymous
The tetrahexyldecyl ascorbate (Vitamin C) in C-Tetra serum is 7%.
Answered by: Anonymous
Date published: 2023-05-24

What percentage of vitamin c does this contain?

Asked by: Anonymous
30%
Answered by: Anonymous
Date published: 2023-03-04
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