C-Tetra™ Advanced Gel-Serum

Medik8

Where to buy Possibly in stock

About this product

The Medik8 C-Tetra™ Advanced Gel-Serum is a serums, essence, ampoule. Our analysis of its 31 ingredients (23 low-risk) rates it Excellent (92/100).

Vegan-friendly Reef-safe

Summarised from our ingredient analysis — not brand marketing copy.

At a glance

Type
Serums, Essence, Ampoules
Ingredients
31
Low-risk
23
Fragrance
Fragrance-free
Origin
United Kingdom

The evidence

Quick Product Notes

Paraben-Free Sulfate-Free Alcohol-Free Silicone-Free EU Allergen-Free Fungal Acne (Malassezia) Safe

Notable Effects & Ingredients

No Notable Effects & Ingredients

Ingredients Related to Skin Types

Good   Bad — tap a skin type to see which ingredients · estimated from ingredient functions
Dry Skin 5/6
Good for dry skin
Sucrose Stearate Squalane Isododecane Sodium Hyaluronate Glycerin
Caution for dry skin
Cellulose Sorbitan Isostearate Sucrose Stearate Xanthan Gum Glycerin Polysorbate 60
Oily/Acne-Prone Skin No data
Sensitive Skin 3/10
Good for sensitive skin
Glycerin Tetrahexyldecyl Ascorbate Hydroxyacetophenone
Caution for sensitive skin
Cellulose Gum Isododecane Glycerin Camellia Sinensis Leaf Citric Acid Sodium Benzoate Phenoxyethanol Linalool Limonene Citral

Ingredients list

31 total
Lower hazard (1) Higher hazard (7)
All31 Skin Conditioning17 Fragrance10 Solvent6 Emulsion Stabilising6 Viscosity Controlling6 Masking5 Perfuming5 Antioxidant5
EWG CIR Ingredient Name & Cosmetic Functions Notes
1
Water
(Solvent)
1
Tetrahexyldecyl Ascorbate
(Antioxidant, Skin Conditioning)
1
B
Isododecane
(Fragrance, Solvent, Emollient, Perfuming)
1
Propanediol
(Solvent, Viscosity Decreasing Agent, Viscosity Controlling)
1
Acetyl Glucosamine
(Skin Conditioning)
1
A
Squalane
(Emollient, Hair Conditioning, Refatting, Skin Conditioning)
TOCOPHEROL
(Antioxidant, Fragrance, Skin Conditioning)
Acetyl Zingerone
(Antioxidant, Chelating, Skin Protecting)
1
B
Camellia Sinensis Leaf
(Perfuming, Skin Conditioning)
1
Hydroxyacetophenone
(Antioxidant)
1
A
Sodium Hyaluronate
(Skin Conditioning, Humectant)
Good for Dry Skin
Good for Dry Skin
1
A
Cellulose
(Absorbent, Bulking Agent, Slip Modifier, Opacifying, Viscosity Controlling)
Avena sativa Kernel Extract
(Abrasive, Antioxidant, Skin Conditioning, Skin Conditioning Emollient)
2
A
Glycerin
(Denaturant, Fragrance, Hair Conditioning, Humectant, Oral Care Agent, Oral Health Care Drug, Skin Protecting, Viscosity Decreasing Agent, Perfuming, Solvent)
Good for Dry Skin
Good for Dry Skin
Fungal Acne
Fungal Acne Trigger
1
Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer
(Emulsion Stabilising, Viscosity Controlling)
citrus grandis peel oil
(Fragrance, Perfuming, Skin Conditioning)
1
Sucrose Stearate
(Skin Conditioning, Emollient, Emulsifying, Surfactant)
1
Tetrasodium Glutamate Diacetate
(Chelating Agent)
1
A
Ethylhexylglycerin
(Deodorant, Skin Conditioning)
1
Acrylates/C10-30 Alkyl Acrylate Crosspolymer
(Emulsion Stabilising, Film Forming, Viscosity Controlling)
1
A
Xanthan Gum
(Binding Agent, Emulsion Stabilising, Skin Conditioning, Surfactant Emulsifying Agent, Viscosity Increasing Agent, Binding, Gel Forming, Viscosity Controlling)
3
A
Sodium Benzoate
(Fragrance, Preservative, Anticorrosive, Masking)
1
A
Cellulose Gum
(Binding Agent, Emulsion Stabilising, Film Forming, Fragrance, Viscosity Increasing Agent, Binding, Masking, Viscosity Controlling)
1
A
1,2-Hexanediol
(Solvent)
3
B
Polysorbate 60
(Emulsifying, Surfactant)
Fungal Acne
Fungal Acne Trigger
1
A
Sorbitan Isostearate
(Emulsifying, Surfactant)
2
A
Citric Acid
(Chelating Agent, Fragrance, Ph Adjuster, Buffering Agent, Masking)
Bad for Sensitive Skin
Bad for Sensitive Skin
4
A
Phenoxyethanol
(Fragrance, Preservative)
Paraben
Paraben
7
Citral
(Flavoring Agent, Fragrance, Masking)
Allergens
Allergens
5
Linalool
(Fragrance, Deodorant, Masking)
Allergens
Allergens
6
Limonene
(Deodorant, Perfuming, Solvent)
Allergens
Allergens

My Ingredient Notes

No personal ingredient notes yet. Save ingredients to your profile to get good/bad alerts here.

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Key ingredients

Tetrahexyldecyl Ascorbate
Antioxidant, Skin Conditioning
Isododecane
Emollient
Acetyl Glucosamine
Skin Conditioning
Squalane
Emollient, Skin Conditioning
TOCOPHEROL
Antioxidant, Skin Conditioning
Acetyl Zingerone
Antioxidant, Skin Protecting

Benefits

No standout benefits flagged for this product.

Concerns

Contains paraben
Contains eu allergen
Not fungal acne (malassezia) safe
Citral — higher EWG
May not suit dry skin
May not suit sensitive skin

EWG flags hazard, not real-world risk — ratings don't account for how much of an ingredient a product contains. Treat these as things to research, not verdicts. How we score →

Ingredients explained

Water
Solvent
Low-hazard ingredient.Read moreShow less
EWG 1 Solvent
Tetrahexyldecyl Ascorbate
Antioxidant, Skin conditioning
Low-hazard ingredient.Read moreShow less
EWG 1 AntioxidantSkin conditioning
Isododecane
Fragrance, Solvent
Low-hazard ingredient.Read moreShow less
EWG 1 CIR B FragranceSolventEmollientPerfuming
Propanediol
Solvent, Viscosity decreasing agent
Low-hazard ingredient.Read moreShow less
EWG 1 SolventViscosity decreasing agentViscosity controlling
Acetyl Glucosamine
Skin conditioning
Low-hazard ingredient.Read moreShow less
EWG 1 Skin conditioning
Squalane
Emollient, Hair conditioning
Low-hazard ingredient.Read moreShow less
EWG 1 CIR A EmollientHair conditioningRefattingSkin conditioning
TOCOPHEROL
Antioxidant, Fragrance
Limited public safety data.Read moreShow less
EWG N/A AntioxidantFragranceSkin conditioning
Acetyl Zingerone
Antioxidant, Chelating
Limited public safety data.Read moreShow less
EWG N/A AntioxidantChelatingSkin protecting
Camellia Sinensis Leaf
Perfuming, Skin conditioning
Low-hazard ingredient.Read moreShow less
EWG 1 CIR B PerfumingSkin conditioning
Hydroxyacetophenone
Antioxidant
Low-hazard ingredient.Read moreShow less
EWG 1 Antioxidant
Cellulose
Absorbent, Bulking agent
Low-hazard ingredient.Read moreShow less
EWG 1 CIR A AbsorbentBulking agentSlip modifierOpacifyingViscosity controlling
Avena sativa Kernel Extract
Abrasive, Antioxidant
Limited public safety data.Read moreShow less
EWG N/A AbrasiveAntioxidantSkin conditioningSkin conditioning emollient
Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer
Emulsion stabilising, Viscosity controlling
Low-hazard ingredient.Read moreShow less
EWG 1 Emulsion stabilisingViscosity controlling
citrus grandis peel oil
Fragrance, Perfuming
Limited public safety data.Read moreShow less
EWG N/A FragrancePerfumingSkin conditioning
Sucrose Stearate
Skin conditioning, Emollient
Low-hazard ingredient.Read moreShow less
EWG 1 Skin conditioningEmollientEmulsifyingSurfactant
+ 8 more — see the full ingredients list above
Sodium Hyaluronate
Skin conditioning, Humectant
Low-hazard ingredient.Read moreShow less
EWG 1 CIR A Skin conditioningHumectant Good for Dry Skin
Glycerin
Denaturant, Fragrance
Low-hazard ingredient.Read moreShow less
EWG 2 CIR A DenaturantFragranceHair conditioningHumectantOral care agentOral health care drugSkin protectingViscosity decreasing agentPerfumingSolvent Good for Dry SkinFungal-acne trigger
Polysorbate 60
Emulsifying, Surfactant
Low-to-moderate hazard.Read moreShow less
EWG 3 CIR B EmulsifyingSurfactant Fungal-acne trigger
Citric Acid
Chelating agent, Fragrance
Skin irritation can occur at high concentrationRead moreShow less
EWG 2 CIR A Chelating agentFragrancePh adjusterBuffering agentMasking Bad for Sensitive Skin
Phenoxyethanol
Fragrance, Preservative
Low-to-moderate hazard.Read moreShow less
EWG 4 CIR A FragrancePreservative Paraben
Citral
Flavoring agent, Fragrance
Higher-hazard ingredient.Read moreShow less
EWG 7 Flavoring agentFragranceMasking Allergens
Linalool
Fragrance, Deodorant
Moderate-hazard ingredient.Read moreShow less
EWG 5 FragranceDeodorantMasking Allergens
Limonene
Deodorant, Perfuming
Moderate-hazard ingredient.Read moreShow less
EWG 6 DeodorantPerfumingSolvent Allergens

How to use

How to use

  • 1 Where it fits: Apply after toner and before moisturiser — thinnest to thickest.
  • 2 Morning works well: Antioxidants like vitamin C pair well with daytime use under sunscreen.

General guidance from this product's category and active ingredients — always follow the directions on the package.

Trust & honesty

Effective levels — general guide

The concentrations these actives are typically effective at in research — not a measurement of this product.

Vitamin C (ascorbic) 5–20%

L-ascorbic acid is usually used at 5–20% (around 10–15% is common). Above ~20% adds little and tends to irritate more; it also needs a low pH to work.

Tetrahexyldecyl Ascorbate

INCI lists don't disclose amounts, and we don't claim to know this product's levels — these are the ranges these ingredients are usually effective at, so you can tell a real formula from "fairy-dusting" a marketed active. How we estimate this.

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