Is ti safe to put carbamide peroxide gel in my invisalign tray?

Yes, but don't.: The carbamide peroxide gel may weaken the invisalign tray, resulting in a less efficient and less effective appliance and force delivery system. Also, if you have attachments on your front teeth, the enamel under/behind the attachments will not bleach and will look darker than the rest of the teeth.

Yes, but would wait: You can you aligners as bleaching trays. However, presumably you teeth are malaligned and by bleaching prior to their alignment you risk an irregular bleaching result. So the best thing would be to defer bleaching until your invisalign treatment is completed.

Whiten with caution: Although many patients do put whitening gel in their trays, patients often overload the tray, resulting in the excess gel being forced up into their gingiva(gums), resulting in irritation. The invisalign trays are designed to fit teeth like a glove, which maximizes their 'gripping'power and their ability to move teeth. This leaves little room for the gel. Whitening trays are more efficient.

Won't work as well: Whitening trays are normally custom made by your dentist with a small reservoir area on the front side of the tooth that holds the gel...The invisalign trays do not have that so they will not work as well.

Almost anything: The tray fits too closely. Talk to your provider.

Yes!: I have told several patients to do this but, remember you will not get any whitening in those areas where you have 'attachments' bonded to your teeth. I hope this helps!

Wait: For all the reasons stated by the other practitioners who have answered this question, best to wait until after aligner tray treatment is completed and you are in retainers. Also note whitening agents will not brighten veneers or caps. So finish your straightening, then do the bleaching.