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? I did not know I was pregnant prior to use, should I be worried? The packaging says the product is flammable, can you travel with it on an airplane? Is the gel safe to swallow? Are the ingredients safe for the environment? Comments 0 comments Article is closed for comments.