Is there any minimum hour of sleep I need to have for the product to work? June 17, 2021 13:16 Updated We recommend a minimum 4-6 hours of contact with teeth. Related articles How long does the Colgate Optic White Overnight Teeth Whitening Pen last? Am I allowed to eat or drink after application? Does the pen cause sensitivity? Can this product replace professional dental cleaning? What is the whitening ingredient in the pen? How does it work? Comments 0 comments Article is closed for comments.