Vitamin C serum — how to choose it and use it

If you had to pick just one ingredient for glow, it would be this: vitamin C. It fades dark spots, evens the tone, protects against sun damage and stimulates collagen. But it's also the ingredient where mistakes cost the most — the wrong formula oxidizes within weeks and does nothing but drain your wallet.

What vitamin C actually does

• Fades dark spots and acne marks — blocks the enzyme that overproduces melanin
• Powerful antioxidant — neutralizes free radicals from sun and pollution
• Stimulates collagen — skin looks plumper, fine lines softer
• Strengthens SPF — under sunscreen, it doubles protection against photo-aging

The types: pure vs derivatives

This is where most people go wrong:

• L-Ascorbic Acid (pure) — the most powerful, but unstable: oxidizes with light, air and heat. Requires a very low pH, which irritates sensitive skin
• Derivatives (ethyl ascorbic acid, ascorbyl glucoside, SAP) — slightly slower, but stable and gentle. For most skin, especially at the start, derivatives are the smart choice

How to choose — the 4 checks

1. Concentration: 5–10% to start; 15–20% only for accustomed skin
2. Packaging: dark glass bottle with pump or dropper — never an open jar
3. Color: fresh serum is clear or slightly yellow; if it's brown, it's oxidized — don't use it
4. Storage: away from light and heat; the fridge extends its life

Arencia Vitamin C Booster Shot uses a stable form of vitamin C — full glow without the oxidation game. If your skin is sensitive, SKIN1004 Tone Brightening Ampoule combines brightening with calming centella.

How to use it — the rules

• Morning, not evening — antioxidants work when the day attacks
• On clean, dry skin, before moisturizer
• 3 times a week at first, then daily once your skin adjusts
• SPF becomes mandatory — vitamin C without sunscreen is half a job; Haruharu Airyfit SPF is so light you won't feel it at all

Who it's for

Dark spots, post-acne marks, uneven tone, dull tired skin — browse the vitamin C serums collection and the dark spots collection. If your skin is very reactive, start with derivatives at low concentration.

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