Is the Colgate Optic White Overnight Teeth Whitening Pen gluten free? June 17, 2021 13:34 Updated Yes, we certify that the Colgate Optic White Overnight Teeth Whitening Pen is gluten free. Related articles What if I am unhappy with the results? Can I swallow my saliva while undergoing treatment? Can I use this with a mouth guard or Invisalign type of braces? Comments 0 comments Article is closed for comments.