Nite White tooth whitener is intended for overnight use. Apply the product at night and remove it in the morning. Alternatively, you can wear this tooth whitener during the day. If you choose to do that, wear it for two to four hours at a time and you can do this one to two times per day. Be aware of the fact that there is a stronger version of this gel that has a more concentrated bleach (22% compared to the 10% to 16% strength of the overnight gel). If you choose to use this version of the product then only wear it for 30 to 60 minutes once per day.

On the Other: Start with Less Time

Regardless of whether you choose to use the overnight product or the stronger daytime bleach product, you want to make sure that you start slowly. The times suggested above are the maximum times that you should wear this product. When starting to wear the product for the first time, begin by leaving it on for only 30 minutes. Check for any tooth sensitivity that this causes and then work your way up to the maximum allotted time.

Bottom Line

The amount of time that you should leave Nite White Tooth Whitener on your teeth depends on two factors: which product you are using and how long you have been using it for. If you're using the overnight product then you can choose to use it all night long or for shorter periods during the day. If you're using the stronger bleach product then you should wear it for no longer than 60 minutes per day. In either case, be sure to start with less time and work your way up to this amount for safety reasons.

Source:

Dentist.net: Nite White Teeth Whitening Instructions

Dentist.net: Nite White Teeth Whitener