Great question. It is not known precisely how much of any given tincture or spray is absorbed into the oral mucosa and how much makes it into the digestive track. This is important because the more that is absorbed directly the less chance it has to be metabolized in the liver, which is something called First Pass Effect. It is generally thought that most oral sprays are absorbed readily by the tongue, mouth, and gums thus avoiding the liver almost entirely. It is important to know that at least some of the drug will make it to the liver. Keep that in mind.