Some users speculate about appropriate dosages or methods of application—including whether or not a small amount of THC boosts CBD’s effects, or whether different methods of administration lead to quicker or more significant effects. Some CBD producers also claim that it has a cumulative effect, and so needs to be used regularly to produce a benefit. But Grant says it’s tough to say at this point exactly how people should (or shouldn’t) be using CBD.
^ Nadulski T, Pragst F, Weinberg G, Roser P, Schnelle M, Fronk EM, Stadelmann AM (December 2005). "Randomized, double-blind, placebo-controlled study about the effects of cannabidiol (CBD) on the pharmacokinetics of Delta9-tetrahydrocannabinol (THC) after oral application of THC verses standardized cannabis extract". Ther Drug Monit. 27 (6): 799–810. doi:10.1097/01.ftd.0000177223.19294.5c. PMID 16306858.
While CBD can be extracted from non-hemp varieties of the plant, hemp-derived CBD is less restricted by the government because of its inherently low levels of THC. CBD from hemp is legal for sale in most US states, while CBD products derived from non-hemp varieties can contain noticeable amounts of THC, and are therefore subject to stricter laws and regulations.
The FDA’s refusal to allow companies to market CBD as a dietary supplement is based on the fact that federal classification as a dietary supplement requires that a substance has not been authorized for investigation as a new drug or medicine. Since Epidiolex has been studied in clinical trials by GW Pharmaceuticals going back several years now and was granted orphan drug status by the FDA in 2013, CBD cannot therefore be classified as a dietary supplement. Or so the FDA says. But cannabis companies are arguing that they started marketing CBD as a dietary supplement before there were any drug trials involving CBD, such that they should still be allowed to claim dietary supplement status for their products. Thus far however, the FDA isn’t budging on this issue.