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 Is there an interval in between treatment cycles? How much time should I wait to go through the whitening cycle again? How long does the Colgate Optic White Overnight Teeth Whitening Pen last? Can this product replace professional dental cleaning? Am I allowed to eat or drink after application? The formula left a film on my teeth, how do I remove this? Comments 0 comments Article is closed for comments.