I am also highly skeptical of products like this, however, I won a free bottle of this in a contest and decided to give it a try.
I decided to try it out on my moms poodle- the vet said she needed a cleaning but my mom was putting it off because her poodle has CT and therefore going under isnt great for her. We were all SHOCKED, including the vet, at how great it worked. She sprayed it in her mouth twice a day for 30 days like the instructions say and A LOT of the tartar and yellowing went away, now the vet says she no longer needs a cleaning.
I give the product