C-Tetra® Advanced — Reddit Reviews
by Medik8
Updated November 10, 2026
20% tetrahexyldecyl ascorbate improves dullness and acne marks; gentle daily serum.
What the community says
A 20% tetrahexyldecyl ascorbate serum with squalane and sodium hyaluronate, built for people who want vitamin C without ascorbic-acid irritation. It layers into morning routines, though flushing-prone skin can still react.
What this means for you
Backed by 15 threads from r/SkincareAddiction, r/koreanskincare and 5 more.
Read the threads ↓What people love
- 20% tetrahexyldecyl ascorbate derivative for daily-use vitamin C
- Sensitive-skin users report zero irritation
- Thin cream texture with moisturizing slip
Watch out for
- Vitamin C can trigger flushing in rosacea-prone skin
- Results may be modest; one user saw only 3–5% enhancement
Product details
Concerns
Skin Type
Product Traits
Key Ingredients
Where to buy
What the science says
Vitamin C has some evidence for fading dark patches, especially melasma, and most studies found it worked better than a placebo 1. For signs of aging, vitamin C has some evidence of smoothing wrinkles, roughness, and uneven tone in sun-damaged skin, though it did not clearly beat a placebo for skin hydration 2.
- Vitamin C for hyperpigmentation Some evidence · 19 studies
- Vitamin C for anti-aging Some evidence · 12 studies
Research context, not treatment advice. Studies are about the ingredient, not necessarily this exact product.
How we grade researchFull ingredient list · 31
Medik8 C-Tetra® Advanced ingredients
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
Listed in label order, highest concentration first. Linked ingredients have their own page.
Real Reddit threads — 23 mentions across 15 threads
Medik8 C-Tetra® Advanced on Reddit, in one place — 15 threads from r/SkincareAddiction, r/koreanskincare and 5 more, summarized.
“Medik8 advanced tetra c has been incredible for my skin (no ascorbic acid)”
Positive
“I have super sensitive skin and it does not tolerate any formula that has Ascorbic Acid in it”
Positive
“So I'm forced to get derivative-based formulas.”
Positive
“If you're focusing on THD, you can't really beat Medik8 C-Tetra Advanced, which I used (and loved) for two years!”
Positive
“As someone who'd never used L-Asorbic Acid before, I thought there'd be a transition time, but I experienced zero irritation and was quickly able to make it a daily product.”
Positive
“More recently, I've been interested in exploring L-Asorbic Acid.”
Positive
“I use their C-Tetra Advanced for Vitamin C”
Positive
“I've loved everything I've tried from Medik-8.”
Positive
“I use their C-Tetra Advanced for Vitamin C and their Liquid Peptides Advanced MP for my peptide serum.”
Positive
“Medik8's C-Tetra Advanced, Remedy”
Mentioned
“C-Tetra Advanced”
Mentioned
“Medik8's”
Mentioned
“my favourite products that really make a difference for me: Medik8 vit c”
Positive
“I feel a major difference for things like skin texture, dullness and acne marks.”
Positive
“Signs of ageing take longer though.”
Positive
“Medik8 C-Tetra Advanced”
Positive
“The Medik8 vitamin C is moisturising, it has a thin cream formula.”
Positive
“you can't go wrong with my prior Vitamin C, C-Tetra Advanced MP from Medik8, which was a pleasure to use!”
Positive
