BurgerClosechevronBagSearchUser
  • Delivery country: United Kingdom
  • servicesStores & services
    Belfast, Victoria Square
    Stores
    Sephora Belfast, Victoria Square
    Victoria Square, Bridge St, Belfast, BT1 4QG
    View All Hours +
    Cycle
    Change your store

    Your favourite store allows you to see services available and book appointments

    In-Store Services
    Make-up and skincare services, Benefit BrowBar, gifting and personalisation workshop, Sephora offers you a whole range of services to come and discover in store Make an appointment
    (Belfast, Victoria Square)
    See Belfast, Victoria Square store servicesView all stores
  • Wishlist
  • Cart0
C-Tetra®

Medik8 C-Tetra® 30ml

%0 4.74 | 1031 reviews
Box

£45.00 (£1.50 per ml)

Free UK delivery

In stock

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

Product Description

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.

See more...

Rated 4 out of 5 by from This serum has a watery, [This review was collected as part of a promotion.] This serum has a watery, but still oily, texture. It does run well in the face and neck. As I am over 50 I really need a higher vitamin C concentration but started with this because I have sensitive skin. I make sure to apply it once my skin has dried from clearing and before moisturizer.
Date published: 2026-05-22
Rated 1 out of 5 by from Cracking for all the wrong reasons [This review was collected as part of a promotion.] Very disappointed as the lid cracked on the lid first time I used
Date published: 2026-05-22
Rated 5 out of 5 by from My favourite serum [This review was collected as part of a promotion.] This is my favourite vitamin C serum, lovely smell, leaves my skin feeling fresh and smooth, ready for my tinted moisturiser. I did try the luxe version but I didn't notice any difference. So I'm back on the trusty original.
Date published: 2026-05-22
Rated 5 out of 5 by from C-Tetra [This review was collected as part of a promotion.] I've only been using this for three weeks, but my skin is already looking brighter, fresher, and it has a lovely glow.
Date published: 2026-05-21
Rated 5 out of 5 by from Glowing skin with this vitamin C [This review was collected as part of a promotion.] The c tetra vitamin c serum is a favourite of mine which I use in the morning it sinks in fast and adds brightness to my complexion and you only need to use a little for full coverage out performing any others I’ve tried.
Date published: 2026-05-18
Rated 5 out of 5 by from Broken Bottle - the top squeeze part came away from the lid [This review was collected as part of a promotion.] I loved the product - however I was only able to use it for approx a week due to the bottle breaking and the entire bottle emptying out into my make up bag - so I feel I wasn't able to get a proper testing of the product. However what I did love was the feel of it - it applied to my skin so smoothly and smelt amazing!
Date published: 2026-05-15
Rated 3 out of 5 by from Good but. . . [This review was collected as part of a promotion.] I love serums with vitamin C and I have tried many different brands. This serum has a very unique consistency due to its oiliness. I should be able to use my serum underneath my cream. This however is too heavy and it takes a long time to sink in before I can apply moisturiser and my skin is very dry. I would not recommend this to someone with an oily skin.
Date published: 2026-05-13
Rated 5 out of 5 by from Gentle yet effective vitamin C [This review was collected as part of a promotion.] A fairly simple yet effective vitamin C serum. Fairly low vitamin C content and just natural fragrance ensure this is well tolerated, even by sensitive skin like mine. I like the way it balances my skins moisture level, which is a welcome side effect. Would recommend this to people with dry sensitive skin, who find it hard to tolerate harsher alternatives.
Date published: 2026-05-13
  • y_2026, m_5, d_24, h_14
  • bvseo_bulk, prod_bvrr, vn_bulk_3.0.46
  • cp_1, bvpage1
  • co_hasreviews, tv_59, tr_969
  • loc_en_GB, sid_92833, prod, sort_[SortEntry(order=SUBMISSION_TIME, direction=DESCENDING)]
  • clientName_sephora-uk
  • bvseo_sdk, p_sdk, 3.2.0
  • CLOUD, getReviews, 108ms
  • REVIEWS, PRODUCT

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
  • y_2026, m_5, d_24, h_14CST
  • bvseo_bulk, prod_bvqa, vn_bulk_3.0.46
  • cp_1, bvpage1
  • co_hasquestionsanswers, tq_3
  • loc_en_GB, sid_92833, prod, sort_[SortEntry(order=LAST_APPROVED_ANSWER_SUBMISSION_TIME, direction=DESCENDING)]
  • clientName_sephora-uk
  • bvseo_sdk, p_sdk, 3.2.0
  • CLOUD, getContent, 127.31ms
  • QUESTIONS, PRODUCT