BurgerClosechevronBagSearchUser
  • Logo
  • servicesStores & services
    Liverpool One
    Stores
    Sephora Liverpool One
    5 South John Street, Liverpool One Mall, Liverpool, L1 8BU
    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
    (Liverpool One)
    See all store services
  • Wishlist
  • Cart0
Medik8 C-Tetra® 30ml

Medik8 C-Tetra® 30ml

%0 4.73 | 823 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.

+Offer

FREE Advanced Day Total Protect 50ml when you spend £95 on Medik8.*

*One free gift per order. Valid until the 11th of August or whilst stock lasts. Your free gift will automatically add to the shopping bag page. Total value at order summary must be £95 or more worth of Medik8 products, after any Promotion Code, Brands You Love discount and before delivery charges are applied. Excludes Gift Voucher 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

See more...

Rated 5 out of 5 by from After consistent use, I’ve noticed After consistent use, I’ve noticed a visible improvement in skin firmness and elasticity. It helps repair and replenish overnight, making my skin look more refreshed and radiant the next day. The antioxidant-rich formula feels soothing, especially after using active treatments like retinoids. Overall, it’s a fantastic product for restoring and strengthening the skin barrier while you sleep. Highly recommended for anyone looking to wake up with healthier, more revitalized skin!
Date published: 2025-07-20
Rated 5 out of 5 by from Great product This has made a great difference to my skin. It is so hydrating and gives my skin a glow. The best I have ever used.
Date published: 2025-07-19
Rated 5 out of 5 by from I really do like the I really do like the way this product goes on the skin and feels once applied - pleasant smell of I would say orange As for the usage - softens the skin I’ve been having microneedling and seems to work well with this on reduction of the wrinkles
Date published: 2025-07-18
Rated 5 out of 5 by from Favourite Vitamin C My go-to vitamin C, it's texture is so light and it soaks in to the skin really well. Smells nice and is a little boost every morning! My skin has certainly appeared more even since using it.
Date published: 2025-07-18
Rated 5 out of 5 by from I absolutely love this product. I absolutely love this product. It’s the only vitamin c that I can use without irritation.
Date published: 2025-07-17
Rated 5 out of 5 by from The foundation of my skin care Always use a Vitamin C as it supports my skin, and I consider it the foundation of my skincare.
Date published: 2025-07-16
Rated 5 out of 5 by from Outstanding x best stuff ever Outstanding x best stuff ever and glow all day long
Date published: 2025-07-16
Rated 5 out of 5 by from I love the c-tetra as I love the c-tetra as it absorbs well and brightens my skin
Date published: 2025-07-13
  • y_2025, m_7, d_24, h_8
  • bvseo_bulk, prod_bvrr, vn_bulk_3.0.42
  • cp_1, bvpage1
  • co_hasreviews, tv_55, tr_764
  • 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, 28.76ms
  • 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_2025, m_7, d_24, h_8CST
  • bvseo_bulk, prod_bvqa, vn_bulk_3.0.42
  • 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, 30.46ms
  • QUESTIONS, PRODUCT