The Vitamin C 13 Serum — Reddit Reviews
by COSRX
Updated September 2, 2026
Gentle 13% vitamin C serum fades dark spots and soothes sensitive, rosacea skin.
What the community says
This 13% vitamin C serum is praised for fading hyperpigmentation and calming sensitive, rosacea-prone skin. It absorbs quickly and is less irritating than stronger vitamin C versions. The only drawback is a strong meat broth-like odor for some users.
What this means for you
Backed by 6 threads from r/koreanskincare, r/30PlusSkinCare and 1 more.
Read the threads ↓What people love
Watch out for
Product details
Skin type data limited
Real Reddit threads — 7 mentions across 6 threads
COSRX The Vitamin C 13 Serum on Reddit, in one place — 6 threads from r/koreanskincare, r/30PlusSkinCare and 1 more, summarized.
“you could try COSRX vitamin C 13 to start”
Mentioned
“it’s a lower concentration”
Mentioned
“feels more gentle and much less irritating than the 23 version.”
Mentioned
“I decided to try the Cosrx Vitamin C serums. I started out with the 13 one and apply it in the morning under moisturizer and sunscreen.”
Positive
“There has been zero irritation from the serum, the only small con is that it smells like meat broth.”
Positive
“I’ve finished one bottle of Vitamin C 13 so far.”
Positive
“I've used COSRX for a while (daily for about 2 years) both C13 and C23.”
Positive
“Loved that it was effective with dark spots, absorbed quickly, and cost effective.”
Positive
“I have sensitive, rosacea prone skin... and nothing but Cosrx worked like wonder.”
Positive
“I like the COSRX vitamin c 13 serum.”
Mentioned
“There’s also a 23% version available.”
Mentioned
“COSRX 23% is incredible”
Mentioned
“I keep my COSRX Vitamin C 13 serum in the fridge and it oxidizes very slowly.”
Positive
“It doesn't cause me to break out either”
Positive
“it's not very sticky compared to other vitamin c products I've tried.”
Positive
“Morning routine: wet cotton round to wash, cosrx vitamin C13, first aid 5 in 1 eye cream, round labs sunscreen”
Positive
“I have been doing this same skincare routine for about two years and this is the best my skin has ever looked.”
Positive
“I know it’s not that bad now but that doesn’t mean it can’t be improved a little bit.”
Positive
