Compare Products: The Niacinamide 15 Serum vs Niacinamide Brightening Toner

COSRX

The Niacinamide 15 Serum

Mid-range15%
$25 / 20ml — $1.25/ml
Good Molecules

Niacinamide Brightening Toner

Budget3%
$14 / 120ml — $0.12/ml

Who It's Designed For

COSRX
  • Oily and acne-prone skin seeking serious oil control
  • Post-acne marks and hyperpigmentation
  • Enlarged pores and textured skin
  • Users ready to step up from 10% to higher-strength niacinamide
  • Those who prefer minimal-ingredient formulas
Good Molecules
  • Those seeking gentle brightening without high-concentration actives
  • Users who want multiple brightening ingredients working together
  • Sensitive skin types who cannot tolerate 10% niacinamide
  • People targeting hyperpigmentation, dullness, and uneven tone
  • Those who prefer toner format over serum

Key Ingredients

COSRX

Niacinamide (15%), Acetyl Glucosamine (2%), Zinc PCA (1%), Allantoin (0.1%)

Good Molecules

Niacinamide (3%), Arbutin (2%), Licorice Root Extract, Ethyl Ascorbic Acid

Product Composition

26% similarity (6 ingredients in common)

Shared Ingredients
waterniacinamide12-hexanediolethylhexylglycerinsodium phytate
Only in COSRX (10)
pentylene glycolbutylene glycolacetyl glucosaminezinc pcatrehalosexanthan gumpullulanallantoincitric acidtocopherol
Only in Good Molecules (7)
arbutin (2.0%)propanediol (2.0%)betaine (0.5%)carbomer (0.06%)tromethamine (0.04%)theobroma cacao (cocoa) seed extractdextrin

User Feedback Patterns

COSRX
Oil control standout

Users consistently report significant reduction in daytime oil and shine. Many describe it as the best niacinamide serum they have tried for sebum control.

Lightweight texture praised

Unlike some high-concentration serums, this absorbs quickly without tackiness or residue. Layers well under other products.

Small bottle concern

The 20ml size (vs. 30ml standard) is a common gripe, especially given the price point.

Pore improvement takes time

Users report visible pore improvement around the 3-4 week mark with consistent twice-daily use.

Good Molecules
Gentle and effective for sensitive skin

Users with sensitive skin report good tolerance. The lower niacinamide concentration avoids irritation common with 10% formulas.

Improved skin brightness

Many users report brighter, more even-looking skin after consistent use. Results typically noted after 4-8 weeks.

Texture improvement

Users note smoother skin texture and smaller-looking pores with regular use.

Not hydrating enough for dry skin

Some users with dry skin find the toner is not moisturizing enough on its own and needs to be followed by additional hydration.

Slight tackiness

Some users note a slight tacky feeling after application, though this absorbs with time.

Which Should You Buy?

Good Molecules Niacinamide Brightening Toner offers great value at a lower price point. COSRX The Niacinamide 15 Serum may be worth the premium if you want Niacinamide (15%).

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