Most human studies of CBD have been done on people who have seizures, and the FDA recently approved the first CBD-based drug, Epidiolex, for rare forms of epilepsy. Clinical trials for other conditions are promising, but tiny. In one Brazilian study published in 2011 of people with generalized social anxiety disorder, for example, taking a 600-mg dose of CBD (higher than a typical dose from a tincture) lessened discomfort more than a placebo, but only a dozen people were given the pill.
As with a fermented food like kombucha, slight natural variations are normal and to be expected in a product such as CBD oil because it is made from living plants. Changes in the weather, soil, and water can all impact the biology of the source material. While we verify Certificates of Analysis (and take many other criteria into consideration during our review process), even the most reputable five-star companies have no way to control for every variable in this organic process.
Fill the dropper with the CBD oil, place the tip of the dropper under the tongue and drip in the desired amount. Let the CBD oil get adsorbed for 1-5 minutes before swallowing it. If you are having a hard time with the dosage or the number of drops when you drip it under your tongue, you can also use a spoon. Just put the desired amount of CBD oil on the spoon and try to put it under the tongue. Just lick off the remaining oil on the spoon. Due to the fine blood vessels and mucous membranes in the mouth, the CBD quickly enters the bloodstream and therefore has a good bioavailability.