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 | 1001 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.

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 Mystery Gift, when you spend £80 on anything.*

One free gift per order. Valid until the 22nd of April, or whilst stock lasts. Your free gift will automatically add to the shopping bag page. Total value at order summary must be £80 or more worth of products, after any Promotion Code, Brands You Love discount and before delivery charges are applied.

Shop this offer

See more...

Rated 5 out of 5 by from Freebie C-Tetra [This review was collected as part of a promotion.] Love using this every morning! Also smells like oranges which is nice!!!
Date published: 2026-04-16
Rated 5 out of 5 by from Nice on the skin & easy to use [This review was collected as part of a promotion.] I really like the results using the vitamin c serum & the bottle is great for use/ you can see exactly what is left and when you need to reorder! Since I've been using the serum my skin is brighter - I do find the texture very slightly oily which is why I prefer the advanced but fit normal skin this is brilliant
Date published: 2026-04-16
Rated 5 out of 5 by from Vitamin c [This review was collected as part of a promotion.] Great for texture and I had a couple of scars with has lightened
Date published: 2026-04-15
Rated 5 out of 5 by from A must!! [This review was collected as part of a promotion.] Great product. I bought it as a gift to many of my friends.
Date published: 2026-04-15
Rated 5 out of 5 by from C-=Tetra [This review was collected as part of a promotion.] Using C-Tetra has improved my completion. It helps with skin texture and absorbs quickly.
Date published: 2026-04-15
Rated 5 out of 5 by from C Tetra [This review was collected as part of a promotion.] A lovely product to use. I have used it for a while now and have noticed a difference in the clarity and hydration of my skin.
Date published: 2026-04-15
Rated 5 out of 5 by from Lifting [This review was collected as part of a promotion.] I love this product as part of my morning routine. It really lifts my skin and smells great.
Date published: 2026-04-15
Rated 5 out of 5 by from Light formula, makes my skin Light formula, makes my skin feel so soft, bright and radiant. Its also suitable for sensitive skin. I keep reordering this product because it visibly improves how my skin looks and feels.
Date published: 2026-04-14
  • y_2026, m_4, d_19, h_8
  • bvseo_bulk, prod_bvrr, vn_bulk_3.0.43
  • cp_1, bvpage1
  • co_hasreviews, tv_58, tr_939
  • 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, 28.56ms
  • 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_4, d_19, h_8CST
  • bvseo_bulk, prod_bvqa, vn_bulk_3.0.43
  • 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, 27.6ms
  • QUESTIONS, PRODUCT