COSRX Vitamin C 23 vs. Goodal Green Tangerine

Both target dark spots and brightening with vitamin C as the headline active, but they take genuinely different approaches to the ingredient itself, and land at very different prices per milliliter.

COSRX uses pure L-ascorbic acid at a real, high 23% concentration, the most potent and most irritation-prone form of vitamin C. Goodal uses green tangerine extract, a gentler, plant-derived vitamin C source with a genuine, repeated Korean-market bestseller record behind it. That's the actual decision most vitamin C shoppers face: potency versus gentleness with real market validation.

COSRX runs $1.25 per milliliter ($25.00 for 20mL). Goodal runs $0.58 per milliliter ($23.00 for 40mL). COSRX costs more than double per mL, in a bottle less than half the size.

COSRX layers 23% pure L-ascorbic acid with a second, more stable derivative (3-O-Ethyl Ascorbic Acid), plus niacinamide, squalane, and adenosine. Goodal centers on 70%-concentration green tangerine extract, a naturally-derived vitamin C source, alongside niacinamide and glutathione, with a simpler overall ingredient list.

Goodal placed #1 in Olive Young's serum category in 2024, then #2 in 2025, a genuine, repeated Korean bestseller signal. COSRX has no comparable award data. On formula strength, pure L-ascorbic acid at 23% is a real, higher-potency active, with a correspondingly higher irritation risk and shorter shelf life once opened than Goodal's gentler, extract-based approach.

If you want maximum vitamin C potency and don't mind a higher price and some irritation risk, COSRX is the stronger, more aggressive option. If you want a gentler formula with a genuine, repeated bestseller record behind it at less than half the per-mL cost, Goodal is the safer and better-value pick for most people.

See our full best Korean serums by concern guide, or browse the rest of our serum coverage.