The Vitamin C 23 Serum — Reddit Reviews
by COSRX
Updated August 19, 2026
23% vitamin C serum brightens and fades hyperpigmentation; strong scent and stings.
What the community says
A high-potency vitamin C serum with added hyaluronic acid for hydration, admired for brightening and reducing dark spots. Best for users experienced with active ingredients who can tolerate tingling. It has a sticky texture, strong orange scent, and risks irritating sensitive or eczema-prone skin.
What this means for you
What people love
- High 23% vitamin C concentration for brightening and fading hyperpigmentation
- Pure vitamin C formula absorbs quickly and is cost-effective
- Includes hyaluronic acid for additional hydration
Watch out for
- Strong, hotdog-like scent disliked by many users
- Can sting or cause redness, especially on sensitive skin or with eczema
- Potential to damage skin barrier if overused or layered improperly
Product details
Use caution
Concerns
Skin Type
Key Ingredients
Where to buy
Real Reddit threads — 50 mentions across 20 threads
COSRX The Vitamin C 23 Serum on Reddit, in one place — 20 threads from r/koreanskincare, r/AsianBeauty and 3 more, summarized.
“COSRX Vitamin C 23”
Mentioned
“I forgot what some of the products I've tried but here are some of what I can remember.”
Mentioned
“I've also tried other brands from other countries.”
Mentioned
“Cosrx vitamin c is the only product that my skin had a bad reaction to 😩”
Cautionary
“the vitamin c gave me a dermatitis-like rash.”
Cautionary
“I love this cosrx vitamin c!!!”
Cautionary
“Currently popular in my circle: vt reedle shot and pdrn, innisfree retinol, round lab sunscreen, aestura, numbuzin, torriden, cosrx vitamin c 23, mediheal masks, iope retinol, d'alba sunscreen, cell fusion c sunscreen”
Mentioned
“People here don’t touch the following brands much:”
Mentioned
“Why is CosRx not popular?”
Mentioned
“Their new vit-c serum blew up last year”
Mentioned
“all due to the fact they used old IOPE formula”
Mentioned
“I’m hoping here AP will release some of their old premium formulas under Cosrx”
Mentioned
“The vitamin c serum by cosrx. Does an amazing job with brightening!”
Positive
“Oh wow so many great products to choose from but I definitely would grab a bunch of Cosrx”
Positive
“I just bought the Cosrx vit c 13 and I like it so far.”
Positive
“Cosrx vitamin c 23. I used it twice a day for about 4 months and I saw results in the first week.”
Positive
“Agree with CosRx Vit C.”
Positive
“it did brighten my skin well.”
Positive
Dupes & Alternatives
Anua
Azelaic Acid Hyaluron Redness Soothing Serum
Better for Hyperpigmentation
5 shared traits
549 mentions
