How Long Does One Need to Wait After Brushing to Whiten Teeth?

You're right to brush your teeth before applying whitening gel.  It is important for your teeth to be free of plaque to absorb the whitening agent.  However, you do not need to wait after brushing.  Rinse out the toothpaste well and then apply the whitening agent.  Best, Dr. Elizabeth Jahanian

Yes your teeth should be clean before whitening, so rinse well to make sure all of the toothpaste is gone and then use the take home whitening.  You mention that you are using a take home whitening kit but you did not mention whether it came from your dentist or purchased at a store.  You can actually get take home whitening kitsfrom your dentist with trays made to fit your teeth with a stronger percentage of bleach than you can purchase at the store for about the same price.  It is safer to have a dentist at least examine your teeth before you apply whitening since it can be very painful if you have decay that you are not aware of or irritated gum tissue,