The Vitamin C 13 Serum

Vitamin C serums can be temperamental—unstable, irritating, or just plain weak. COSRX's version actually works without the drama. It's a stable 13% L-ascorbic acid formula that brightens dull tropical skin and tackles early fine lines, without the redness that usually comes with vitamin C. If your skin gets angry easily, this one's gentle enough to handle.

Why You'll Love It

• Stabilized vitamin C that actually stays potent (no brown discoloration nonsense)
• Brightens in weeks—cuts through the dullness humidity traps in your skin
• Hydrating, not drying—it won't leave your face feeling tight or irritated
• Works well with sensitive skin types, even if you're using actives like niacinamide

Key Ingredients

L-Ascorbic Acid (13%) — The gold standard form of vitamin C. It brightens, boosts collagen, and protects against environmental stress. 13% is the sweet spot: strong enough to work, gentle enough for daily use.

Ferulic Acid & Vitamin E — Stabilizers that keep the vitamin C from oxidizing and multiplies its antioxidant power.

How to Use

After cleansing, apply a few drops to damp skin. Wait 10–15 minutes to let it absorb. Follow with your regular hydrating toner or essence. This is your Treat step. Use once daily (morning is best) to avoid overloading sensitive skin.