No.5 Vitamin Concentrated Serum — Reddit Reviews
by numbuzin
36mentionsacross 8 Reddit threads
Updated July 20, 2026
What the community says
Niacinamide and vitamin C serum often praised for fading stubborn hyperpigmentation and brightening combination skin, but can be heavy and trigger irritation or breakouts especially on sensitive or acne-prone skin.
What people love
- Niacinamide and melanin inhibitors combo that's visibly effective for fading dark spots and acne scars
- Provides a noticeable dewy glow and mild hydration, suitable for layering under makeup
- Favored in K-beauty circles with documented efficacy on stubborn hyperpigmentation over weeks
Watch out for
- Can provoke cystic acne or breakouts, making it risky for active acne sufferers
- Some users report irritation and redness, especially those with sensitive skin or when using alongside exfoliants
- Texture feels heavy or sticky, particularly problematic in hot weather or on oily skin types
Product details
Use caution
Concerns
Skin Type
Key Ingredients
Where to buy
Real Reddit threads
8 threads from r/koreanskincare, r/tretinoin +1 more
Dupes & Alternatives
Anua
Azelaic Acid 10 Hyaluron Redness Soothing Serum
Better for Hyperpigmentation
5 shared traits
352 mentions
