Our Vitamin C + E + Ferulic Acid Serum is dermatologist-approved and safe for daily use. SKIN BRIGHTENING SERUM – Contains 15% L-Ascorbic Acid—the purest and most potent form of Vitamin C at 99.9% purity, unlike lower-efficacy alternatives that use Sodium Ascorbyl Phosphate (only 45–55% Ascorbic Acid).