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C-Tetra®

Medik8 C-Tetra® 30ml

%0 4.72 | 869 reviews
Box

£42.00 (£1.40 per ml)

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 1 out of 5 by from Unfortunately not for me I use Differin - Vit A - and using this in the morning and Differin in the evening for the last two and a bit weeks completely wrecked my skin leaving it sore, dry and breaking out in spots. Even now a week on from not using the Vit C it's still a mess. I am very precious about my skin as I have had a lot of acne issues and now I am having to try and sort out the mess. I love your other products but this isn't good for my skin.
Date published: 2025-12-10
Rated 5 out of 5 by from Essential part of my night time routine This product is expensive but it is worth the money. You can feel it absorb in to your skin but it does not feel heavy or stickly. Skin feels very moisturised afterwards. I use it after cleanser as part of my night time routine as it feels too heavy to wear under make up.
Date published: 2025-12-04
Rated 5 out of 5 by from Feels luxurious Love this product. Feels lovely on my skin and lasts well
Date published: 2025-12-03
Rated 5 out of 5 by from Vit C Really excellent serum (I have very sensitive skin and I haven't broken out at all)
Date published: 2025-12-03
Rated 5 out of 5 by from Favourite skincare staple I've been using this for a year now and see a significant improvement particularly at this time of the year when I'm prone to rosacea. My skin is calmer and it feels like a luxurious treat every day
Date published: 2025-12-03
Rated 1 out of 5 by from Bad reaction & use with caution I bought this a while ago but needed to still finish my old serum. I patch tested it and had no reaction to it within 24 hours. I used it two days ago and had no issues. Used it again today and not only it seemed my skin „darkened” right after application - did not get fully red but it seemed like it was a mild reaction. By the end of the day my entire forehead is irritated with tiny little red spots that are slowly turning into whiteheads. The serum has a quite strong citrusy scent so I believe it is the grapefruit peel oil that’s causing the reaction. Not sure if that is included for scent only or if that’s for vit c content. I think it’s the former and that’s a shame. This was supposed to work for sensitive skin. Back to Glossier once my skin returns to normal. Use only if you can risk your skin/wallet.
Date published: 2025-11-29
Rated 5 out of 5 by from Wow love this Vit-C I've been using this product for 6 months now and skin feels hydrated and very glowy! A little goes a really long way so great value for money.
Date published: 2025-11-21
Rated 5 out of 5 by from Love this. Think it really Love this. Think it really smooths my skin and is reasonably priced for the great quality of product. I’ve purchased for all my family!
Date published: 2025-11-19
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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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