Vitamin C: effective % & pH 비타민C
⚡ Quick answer: Vitamin C: effective concentration 10–20% (L-ascorbic acid); derivatives vary 1–10%, optimal pH <3.5 (L-ascorbic acid); derivatives 5–7, evidence Strong. For pure vitamin C, 10–20% at low pH is the effective window; a gentler '5% derivative' is a different, milder molecule — don't compare the numbers directly.
How much Vitamin C actually works? Here's the dosage, pH and evidence — the formulator-level read behind the % on a Korean label.
| Effective % | 10–20% (L-ascorbic acid); derivatives vary 1–10% |
|---|---|
| Optimal pH | <3.5 (L-ascorbic acid); derivatives 5–7 |
| Evidence | Strong |
| Onset | 4–12 weeks |
What the % on the label really means
For pure vitamin C, 10–20% at low pH is the effective window; a gentler '5% derivative' is a different, milder molecule — don't compare the numbers directly.
⚠️ Ceiling: Above ~20% L-ascorbic acid raises irritation with little added benefit and oxidizes faster.
Vitamin C guide →How Vitamin C works →
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Explore the full K-beauty hub →✍️ Written & reviewed by the KoreaPlus Editorial team — dermatologist-informed, cosmetic-science researched & source-cited. Last reviewed 2026-06-21.
General educational information using cosmetic structure-function wording — not medical advice. Always patch-test new actives. © KoreaPlus.