How long does the Colgate Optic White Overnight Teeth Whitening Pen last? June 17, 2021 13:02 Updated The whitening pen can last up to 35 days when used as directed (depending on individual usage) Related articles The packaging says the product is flammable, can you travel with it on an airplane? How long will the whitening effect last? Does the pen cause sensitivity? How do I know if I’ve put enough product on each tooth? How should I clean the pen brush? Comments 0 comments Article is closed for comments.