Vitamin C12 Serum — Reddit Reviews
Updated October 3, 2026
12% vitamin C serum for brightening; strong and can sting.
What the community says
An ascorbic acid serum with glycerin, dimethicone, sodium hyaluronate, and salicylic acid for daytime glow. People use it for dark spots and brightness, but the alcohol, fragrance, and acid combo can sting reactive skin.
What this means for you
What people love
- 12% L-ascorbic acid for glow
- Hydrating slip from glycerin and hyaluronic acids
- Salicylic acid gives it a mild exfoliating edge
Watch out for
- Strong enough to sting or irritate reactive skin
- Alcohol denat and fragrance make sensitivity worse
- Can react badly with other actives like tretinoin or azelaic acid
Product details
Skin type data limited
Where to buy
What the science says
Hyperpigmentation
Some evidence
Vitamin C: 7 studies tested it on its own. See all 24 studies
What the studies found
- Most studies found vitamin C helped fade dark spots or patches
- In melasma studies, vitamin C on the skin often made patches look lighter over time
- Used with other treatments, vitamin C sometimes faded melasma more than the other treatment alone
- For sun spots, vitamin C showed some fading, but one study had mixed results
- It worked about as well as glycolic acid for fading melasma patches in one large review
Research context, not treatment advice. Studies are about the ingredient, not necessarily this exact product.
Real Reddit threads — 15 mentions across 3 threads
La Roche-Posay Vitamin C12 Serum on Reddit, in one place — 3 threads from r/30PlusSkinCare and r/SkincareAddiction, summarized.
“- LaRoche vitamin C12 serum”
Positive
“☀️Morning:”
Positive
“LaRoche vitamin C12 serum”
Positive
“Vitamin C Serum-- just switched to La Roche Posay Vitamin C12 Serum.”
Cautionary
“I switched from the Timeless to the La Roche Posay because I thought reducing the strength might help, but it hasn't really.”
Cautionary
“it seems like whenever I use actives-- which for me means only a retinol and a vitamin c complex---my skin gets pissed off”
Cautionary
“La Roche-Posay Pure Vitamin C12 Serum (12% L-Ascorbic Acid, Salicylic Acid)”
Mentioned
“OUT: LRP Vit C”
Mentioned
“plus salicylic in ur cleanser, ur vit c AND ur effaclar”
Mentioned
