Is the pen safe for enamel? June 17, 2021 13:34 Updated Yes, the Colgate Optic White Overnight Teeth Whitening Pen has an enamel safe formula. Related articles Does the pen cause sensitivity? The packaging says the product is flammable, can you travel with it on an airplane? Is the gel safe to swallow? I did not know I was pregnant prior to use, should I be worried? Are the ingredients safe for the environment? Comments 0 comments Article is closed for comments.