Compare Products: The Niacinamide 15 Serum vs 10% Pure Vitamin C Anti-Aging Face Serum

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
La Roche-Posay
  • Those who trust dermatologist-recommended brands
  • Users with oily or combination skin who benefit from salicylic acid
  • People seeking a moderate vitamin C concentration (10% vs. 15-20%)
  • Those who want hyaluronic acid hydration alongside vitamin C
  • Users looking for a multi-active anti-aging serum

Key Ingredients

COSRX

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

La Roche-Posay

10% Ascorbic Acid (L-Ascorbic Acid), Sodium Hyaluronate, Hydrolyzed Hyaluronic Acid, Salicylic Acid, Neurosensine (Diacetyl Dipeptide-1 Cetyl Esters)

Product Composition

20% similarity (7 ingredients in common)

Shared Ingredients
wateracetyl glucosamine1xanthan gumethylhexylglycerinsodium phytatetocopherol
Only in COSRX (9)
pentylene glycolniacinamidebutylene glycol2-hexanediolzinc pcatrehalosepullulanallantoincitric acid
Only in La Roche-Posay (19)
ascorbic acidcyclohexasiloxanealcohol denat.potassium hydroxidepolymethylsilsesquioxanedimethiconepropylene glycolpentaerythrityl tetraethylhexanoatepeg-20 methyl glucose sesquistearateadenosinepoloxamer 338ammonium polyacryloyldimethyl tauratehydrolyzed hyaluronic acidcaprylyl glycollaureth-7toluene sulfonic acidpolyacrylamidesalicylic acidparfum/fragrance

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.

La Roche-Posay
Smooth, elegant texture

Users praise the lightweight, quick-absorbing texture. The silicone base and alcohol give it a matte, non-sticky finish that layers well under makeup.

Alcohol causes dryness for some

Users with dry or sensitive skin report dryness and irritation, likely from the denatured alcohol. This is the most common negative feedback.

Effective brightening

Users who tolerate the formula report visible brightening and improved skin tone within 3-4 weeks. The 10% concentration works well for most.

Oxidation over time

Like all L-ascorbic acid serums, users report color change within weeks. Some note it darkens faster than competitors.

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