A number of difficulties exist in evaluating published data on CBD or marijuana use for epilepsy. The extremely limited published studies were small, poorly described, and not well designed. Contributing to the difficulty of interpreting published studies, CBD products are not produced under the guidance of good manufacturing practices (GMP) and are not subject to regulations governing labeling, purity, and reliability. In other words, currently, there is no guarantee of consistency between products, or even differing lots produced by the same manufacturer. Without independent testing (e.g. USP certification) of CBD products for content and purity, as well as bioavailability testing of specific products, uncertainty surrounds the use of available CBD products in routine clinical settings.
Other potential side effects include low blood pressure, lightheadedness, and drowsiness, but these have typically only occurred in patients who have exceeded doses of 1,500 mg daily for a period of 4 weeks or more; far more than the average person will need take on a daily basis for chronic pain symptoms. (In fact, the majority of CBD users claim they find an effective dose to be anywhere between 10 and 40 mg daily).
Rather, what most of these oils appear to be are extracts of the hemp seed. As we mentioned earlier, CBD oil can be made from either hemp or marijuana cannabis plants. No matter which plant they come from, however, they must be made using the flowers, leaves, stem and stalks of the plant, as these are the parts where the CBD compound is actually located.