Condition: NWT Retail: $105 Size: 1 fl oz. The Potent-C Vitamin C Power Serum is an anti-aging and brightening Peter Thomas Roth serum with 20% THD Ascorbate-a mega-potent, ultra-stable ingredient 50X more powerful than traditional Vitamin C. Packed with a jaw-dropping concentration of 20% THD Ascorbate Vitamin C This serum's performance is boosted by two ultra-powerful antioxidants 3% Vitamin E and 2% Ferulic Acid Help improve the look of fine lines, wrinkles, firmness, uneven skin tone, texture, brightness and dehydration Key Ingredients: 20% THD Ascorbate - Ultra-stable scientific breakthrough form of Vitamin C that is 50X more powerful than traditional Vitamin C 3% Vitamin E and 2% Ferulic Acid - Help boost the performance of THD Ascorbate Vitamin C while providing antioxidant benefits