Medik8 C-Tetra Advanced on a warm cream background

Antioxidant

Medik8 C-Tetra Advanced

A lightweight 20% THD ascorbate antioxidant emulsion for people who want a potent but wearable vitamin C step.

Best suited to: You want a high-strength vitamin C derivative in a light, slightly hydrating texture.
Another option may be better if: You prefer an oil-based serum or want a simpler, lower-cost antioxidant.

£69.00

Guidance continues after purchase

Doctor-led product guidance

Why this product — and when another may suit you better.

This serum contains an incredibly stable form of Vitamin C called THD ascorbate which is perfect for even the most sensitive skin types. Unlike lots of Vitamin C and anti-oxidant serums this product has a lightweight but creamy texture acting as a fast absorbing but still slightly hydrating base for the next step in your routine. Within the Medik8 C-Tetra range this has the highest concentration of THD ascorbate.

Why it made The Curatory

Vitamin C (in all its forms) is challenging to formulate with. It prefers oilier bases to keep it stable and effective so when a product comes along that sits in a water base and also acts as a lightweight moisturiser it opens the formulation up to a wider group. The reason I loved this product was its versatility. In a hurry? No problem, it’s quick to apply and fast absorbing. Have a bit more time? Amazing, you can layer other products easily on top including makeup. Skin feeling a bit sensitive and you want a break from actives? This and SPF in the morning will get your barrier back in action ASAP.

It may suit you if…

Everyone should have some form of antioxidant in their skincare routine and Vitamin C is at the top of the list for its ability to help support collagen synthesis and help improve/prevent hyperpigmentation. Of all the forms of Vitamin C, THD ascorbate is one of the most stable and suitable for even very sensitive skin. The additional ingredients including phyto exosomes, acetyl zingerone, hyaluronic acid and N-Acetyl Glucosamine help to support the skin barrier and gradually improve your skin’s ability to hold onto water and brighten your complexion with no sensitivity.

Another option may be better if…

This product is suitable for all skin types including those with sensitive and acne prone skin. The formulation has a light weight creamy texture so if you prefer something a bit richer and oil-based you may prefer Medik8 C-Tetra Luxe instead. If you’re looking to slim down your skincare routine and would like an anti-oxidant that also contains niacinamide with other brightening ingredients then the Mesosestetic Age Element Brightening Concentrate may be better for you.

What to expect

Expect gradual support for brightness, tone and overall skin quality rather than an immediate change. Daily sunscreen remains essential.

Product overview

Routine placement Where this fits MorningAntioxidant

A broad guide to where this sits, without assuming how many steps your routine has.

Morning

Cleanse Explore this step

This product Antioxidant

OptionalTargeted Explore this step

Essential final stepSPF Explore this step

How to introduce it

As it’s such a thin, water-based product it should be applied early in your routine and can be used both morning and evening. After cleansing (and toning if this is in your routine) gently massage the product into your face and neck.

Three pumps is plenty for both the face and the neck . Allow to absorb and settle for a few moments before applying any other products over the top.

You shouldn’t be getting any irritation with this product but worth starting with once daily (morning) use for the first two weeks before building up to twice daily.

Guidance continues after purchase. We can help you introduce, simplify or adjust this product.

Inside the formula

The ingredients that make this special

A closer look at the ingredients doing the most meaningful work in this formula—and what the evidence can reasonably tell us.

Tetrahexyldecyl Ascorbate

A highly antioxidant and stable form of Vitamin C that helps prevent and treat aging changes and pigmentation.

Read the clinical context

Tetrahexyldecyl Ascorbate is a mouthful so we call it THD ascorbate which is only marginally better. This is a very stable form of Vitamin C that supports collagen production and mops up free radicals that damage the skin barrier, collagen and DNA. Together this improves overall skin quality, hydration and pigmentation.

Hyaluronic Acid

A potent hydrating ingredient that draws water towards it.

Read the clinical context

Hyaluronic Acid is a moisturising ingredient that helps boost hydration in the skin when combined with other moisturising agents. It falls into the category of humectant moisturisers that draw water into the upper layers of the skin. Works best when combined with emollient and occlusive moisturisers.

Phyto Exosomes

Plant-based exosomes that claim to improve communication between skin cells and help with fine lines.

Read the clinical context

Phyto Exosomes are a trending ingredient at the moment but lots more research is needed before we get too excited. They claim to boost collagen production and iron our fine lines but the jury is still out. They're a nice addition but the real work is done by the other ingredients.

Acetyl Zingerone

A potent, ginger-derived antioxidant that helps prevent environmental stress to the skin.

Read the clinical context

Acetyl Zingerone is derived from ginger as as well as being a potent anti-oxidant in its own right, also helps to stabilise Vitamin C to keep it potent for longer.

N-acetyl Glucosamine

Improves dermal hydration and can help to reduce pigmentation.

Read the clinical context

N-acetyl Glucosamine is the stable form of acetyl glucosamine which is not only a precursor to hyaluronic acid (helping to improve overall skin hydration) but also acts as a skin brightening ingredient by helping to reduce pigmentation.

View the complete ingredients list

Aqua (Water), Tetrahexyldecyl Ascorbate, Isododecane, Propanediol, Acetyl Glucosamine, Squalane, Tocopherol, Acetyl Zingerone, Camellia Sinensis (Green Tea) Leaf Vesicles, Hydroxyacetophenone, Sodium Hyaluronate, Cellulose, Avena Sativa (Oat) Kernel Extract, Glycerin, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Citrus Grandis (Grapefruit) Peel Oil, Sucrose Stearate, Tetrasodium Glutamate Diacetate, Ethylhexylglycerin, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Xanthan Gum, Sodium Benzoate, Cellulose Gum, 1,2-Hexanediol, Polysorbate 60, Sorbitan Isostearate, Citric Acid, Phenoxyethanol, Citral, Linalool, Limonene

The thinking behind the formula

More about Medik8

Medik8 develops and manufactures virtually all of its products at its ISO-certified innovation centre near London. Its in-house scientists focus on formulation, stability and ingredient delivery rather than following a trend simply because it is popular.

Crystal Retinal is a good example. Retinal is an effective but fragile molecule, so Medik8 uses encapsulation, a patented stabilising complex and protective packaging, alongside a ladder of strengths designed for measured progression.