Best Korean serum: what Koreans pick, and how to choose
Korean brands use serum, essence and ampoule for similar products. Here is what the words usually mean, and the five serums Korean Hwahae users rank highest today.
Serum, essence, ampoule
There is no legal difference. In practice an essence is lighter, a serum is a little thicker, and an ampoule is marketed as the most concentrated. Choose by the active ingredient, not the word.
Common Korean serum ingredients
Niacinamide: tone and oil control.
Vitamin C: brightening; can sting sensitive skin.
Centella, mugwort, heartleaf (어성초): soothing.
Retinal or retinol: anti-ageing; use at night and wear sunscreen by day.