This is the portion of a substance (drug or compound), which is absorbed from the body and that enters the circulation and has the ability to produce an effect. A compound given intravenously can have 100% bioavailability, whereas one absorbed from the intestinal tract may have only 5%. The greater the bioavailability of a drug, the less concentrated the product needs to be. If it is not absorbed, it is typically wasted. Broad-spectrum hemp extracts absorption from the intestinal tract ranges from 5-30% but can vary dramatically depending on how it is administered. Some authors have suggested that absorption may be better when a tincture is given with a fatty meal; however, like in humans, if the tincture is given into the mouth (between the teeth and lip in dogs and sublingual in people) it is absorbed directly from the mucous membranes and thus is likely absorbed in higher concentrations and bypasses the first pass effect. The first pass effect means that less drug is active than you actually took because some is lost as it passes through the gastrointestinal system and the liver before reaching the blood stream.