After Dr. Yannis became interested in a sponge soaked in a NAC, he collaborated with space scientists to develop the new and improved formula, NAC Y² ™ It became the principle ingredient in the original 111SKIN product the Y Theorem Repair Serum, and then throughout the entire Reparative range. It is a powerful ingredient in skincare because of its varied and high antioxidant content, helping to improve resilience, protect from environmental aggressors, brighten the complexion, and rejuvenate skin.


  • N-acetylcysteine (NAC): The N-acetyl derivative of amino acid L-cysteine (the precursor for glutathione – an important antioxidant which is produced by the body).
  • Ascorbyl Phosphate: A stable Vitamin C derivative and antioxidant.
  • Aesculus hippocastanum Extract: The active ingredient is Escin, which is an antioxidant and vasoprotector.