GUARANTEED AUTHENTIC: Obtained directly from manufacturer at a dermatology conference. Unopened and sealed box, 1 fl oz. Box was dented while transporting home from the conference but bottle and serum are in new condition. #1 recommended vitamin C serum by dermatologists. Allure Beauty Hall of Fame. Experience the power of SkinCeuticals C E Ferulic Serum. This antioxidant-rich formula in a sleek brown bottle helps protect and rejuvenate your skin.