各种护肤成分的有效浓度

Vitamin A (Retinol): at least 2-3% concentration.

Vitamin C: at least 10% concentration, PH 2-3.

Vitamin E: at least 5% concentration.

BHA: at least 1-2% concentration, PH 3-4.

AHA: at least 5-8% concentration, PH 3-4.