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 | 952 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 Hydr8 B5™ 30ml when you spend £80 on Medik8.*

Achieve a deeply hydrated complexion with Medik8’s original hyaluronic acid serum. 

 

*One free gift per order. Valid until the 1st of April or whilst stock lasts. Your free gift will automatically add to the shopping bag page. Total at order summary must be £80 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.

Shop this offer

See more...

Rated 5 out of 5 by from LOVE THIS! [This review was collected as part of a promotion.] I have sensitive skin and need to be careful with serums but this is such a great product for me. The texture is so soft and such great quality! Perfect consistency before my day-cream.
Date published: 2026-03-28
Rated 5 out of 5 by from Beautiful product [This review was collected as part of a promotion.] Excellent vitamin c product leaves skin looking beautiful
Date published: 2026-03-28
Rated 5 out of 5 by from Game changer [This review was collected as part of a promotion.] Game changer to my skin routine the product I never knew I needed !
Date published: 2026-03-27
Rated 5 out of 5 by from Great Vit C! [This review was collected as part of a promotion.] Lightweight and non-greasy product. Absorbs wonderfully.
Date published: 2026-03-27
Rated 5 out of 5 by from Lightweight + Nourishing [This review was collected as part of a promotion.] So lightweight + nourishing. My skin drinks it in! I’m on me second bottle.
Date published: 2026-03-27
Rated 5 out of 5 by from Excellent [This review was collected as part of a promotion.] My sensitive skin with rosacea loves this form of vitamin C serum.
Date published: 2026-03-27
Rated 5 out of 5 by from Game changer Vit C [This review was collected as part of a promotion.] I have lived using this hydrating, effective vit C serum for years now, along with Liquid peptides in the morning my aging skin is clear , no redness , no brown spots and I love this serum nearly more so than the new one because it's very silky on the skin and really hydrated and brightens all day , I'm prone to breakouts but these serums don't break me out , I won't change brands.
Date published: 2026-03-27
Rated 5 out of 5 by from Great benefits to your skin [This review was collected as part of a promotion.] I have been using this for the last 4 weeks just yo see if there is much of a difference to this one and the normal one I buy c-tetra advanced I find the C-Tetra was smoother to apply feels nicest on the skin but does leave my skin feeling slightly tacky for awhile so takes longer to absorb ,so takes longer to finish my skincare routine in a morning Still gives great benfits to the skin when your consistent with this and honest you will definitely see your skin looking more healthy and smooth ,and always make sure your using a good SPF daily in your skin routine
Date published: 2026-03-27
  • y_2026, m_3, d_30, h_11
  • bvseo_bulk, prod_bvrr, vn_bulk_3.0.43
  • cp_1, bvpage1
  • co_hasreviews, tv_57, tr_877
  • 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, 136.31ms
  • 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_3, d_31, h_9CST
  • 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, 109.29ms
  • QUESTIONS, PRODUCT