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Medik8 C-Tetra

Medik8 C-Tetra

Size: 1.0 oz (30 ml)

Medik8 C-Tetra is an ultra-stable, non-irritating vitamin C serum that helps combat sun damage, boost collagen production, increase skin's elasticity, brighten the complexion and improve overall texture. In addition, this serum also helps protect against free radical damage and minimize hyperpigmentation.

TIA Review by Dennis:
I love Tetrahexyldecyl Ascorbate. Let’s just get that out of the way. Ever since I discovered TA, I thought it was the most exciting ingredient I had come across. I still believe that, and I am always recommending it to family and friends, though they mostly think that I am a skin-obsessed loon. You can imagine how excited I was to be asked to test out the Medik8 C-Tetra Pro-Collagen Vitamin C Formula with 3% Tetrahexyldecyl Ascorbate.

You may have previously read articles describing the merits of TA: it is one of the most, if not the most powerful and stable forms of vitamin C available. Being lipid-soluble means it can easily penetrate the skin, something that can be difficult for water-soluble forms of vitamin C. And there are all sorts of good things that happen once it’s in there: stimulated collagen production, diminished UV damage, suppression of melanogenesis and stimulation of glycosaminoglycans.

Naturally I have tried quite a few serums with TA over the years, and Medik8 C-Tetra might be my favorite so far. It is, however, not without its issues. Not with the product itself, but with the packaging! I find the dropper to be troublesome and overly complicated. I mean, when you have to plot out how you are going to dispense on your next use so that no drops are lost… I find that to be a problem. The watery consistency did not help this. But to be fair, I did kind of become a pro at this after a month of use.

Also, although TA is not supposed to exfoliate or irritate the skin, a few days after I started using Medik8 C-Tetra my neck broke out in a red, itchy rash. I was not sure it was the TA, so I stopped using on my neck for a few days and the rash disappeared. I started using on my neck again after which the redness did not reappear – a slight itch did but that has also since gone away. Still not certain the C-Tetra is to blame, but those with overly sensitive skin might take heed.

I used C-Tetra two times a day: Mornings under sunscreen, which seems to have the added benefit of helping the rather thick MD Solar Sciences Mineral Lotion I use smooth on. I also used at night. It will need to be layered with something more moisturizing. I alternated layering it under my heavier peptide cream and over Skin-Lasting. It seems to play well with anything you want to layer it with.

I also would add a couple drops of C-Tetra to my hands. I mention this because this is where I am seeing the most difference. My hands look plump, healthy, and generally not as frightful as usual. This makes me happy since my hands and my calves are areas on my body I feel mock my skincare efforts. I had been zapping my hands with my PaloVia, using red LED, Retin-A, and sunscreen with some degree of success, but I think C-Tetra has made the most difference. A shame I did not have the foresight to take before-and-after pictures. My face also looks bright, plump and healthy and who doesn’t want that?

According to Medik-8, C-Tetra is best for both men and women in their 20s to 40s. I think people of any age can benefit from a healthy dose of TA. There are some silicones included in the ingredients but every TA serum I have used thus far had silicones on their ingredients list. I always imagined this is because TA is a lipid-based vitamin C? Please someone correct me if I am wrong. Anyway, there is a lot to like about C-Tetra. The dollar price tag might be hard to swallow, but with twice daily use on my face, neck and hands, the bottle has barely gone down. I predict a bottle might last two to four months depending on how much and how often you use.

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Our Take

I love Tetrahexyldecyl Ascorbate. Let’s just get that out of the way. Ever since I discovered TA, I thought it was the most exciting ingredient I had come across. I still believe that, and I am always recommending it to family and friends, though they mostly think that I am a skin-obsessed loon.... read more

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1 Reviews
  • Cindy

    (5 out of 5)

    I love that four simple, but effective ingredients pack such a punch, and give this day cream two thumbs up. I personally experienced improved all-over skin tone, brightening, super hydration, diminished fine lines around my eyes and mouth, and dewy soft skin.

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  • Dennis

    July 4, 2013

    (5 out of 5)

    Thank Marta. I read your review on the CE tetra and I was envious you got to try the 7% formula.

  • Marta

    July 3, 2013


    Great review Dennis. I like the Medik8 CE Tetra (which is similar, but with vitamin E). I think they do these simple formulas really well.

  • Simmondsia Chinensis (Jojoba) Oil
  • Cyclopentasiloxane
  • Cyclohexasiloxane
  • Tetrahexyldecyl Ascorbate
  • Tocopherol Acetate
  • Citrus Grandis (Grapefruit) Peel Oil
  • Limonene

Medik8 Brand Spotlight (VIDEO)

We take a closer look at Medik8, the brand which comes to us from the United Kingdom.

In the morning, after cleansing, apply 3-4 drops directly to the skin and blend evenly across the whole facial area, neck and décolleté. Alternatively, place a drop on your finger and massage into the skin. Leave to absorb for 2-3 minutes.

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