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Isntree · Serum
C-Niacin Toning Ampoule
OY Korea #20 serumUS stock
Vitamin C derivative plus niacinamide in one tone-care ampoule — the sensible brightening pairing.
★ 4.51,900 reviews
BEvidence grade
$25Best total · duties in
lightTexture · Serum
Is this right for your skin? — take the 60-second quiz and this box becomes a personal verdict.
Ingredient check⚠ 1 caution flag
✓ Fragrance-free⚠ Fungal-acne safe✓ No drying alcohol✓ Essential-oil free✓ Pregnancy-cautious free
Evidence checkGrade B · MFDS ✓
🇰🇷 MFDS-certified functional cosmetic — brightening (미백)Filed with Korea's FDA as 「이즈앤트리씨나이아신토닝앰플」 — a regulator-reviewed efficacy claim, not a marketing one.
Grade B — Solid transparency and consistent ratings; limited third-party clinical data (seed draft — verify before launch).
How grading works
Scored on clinicals · certifications · cross-platform rating consistency · transparency. Brands can't pay to change this.
What Korea says#20 serum
#20 serum · Olive Young Korea (seed) · Rank indicative — weekly verification pending
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Where to buybest total $25
| Retailer | Price | Ship + duty | Total | |
|---|---|---|---|---|
| Amazon ✓ official Official store — verify seller before launch Pays: Visa · MC · Amex · Discover · Amazon Pay · Affirm | $25 | — | $25BEST | Shop → |
| Olive Young Global ✓ official Ships from Korea 7–14d · +15% duty Pays: Cards · PayPal · Apple Pay · Alipay+ | $20 | $10.00 | $30 | Shop → |
Totals include estimated import duty on Korea-shipped orders (15%, post–de minimis). Links open retailer search; production uses exact product affiliate links. Payment methods indicative — verify at checkout.
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