The 2014 Farm Bill legalized the sale of "non-viable hemp material" grown within states participating in the Hemp Pilot Program. This legislation defined hemp as cannabis containing less than 0.3% of THC delta-9, grown within the regulatory framework of the Hemp Pilot Program. The 2018 Farm Bill allowed for interstate commerce of hemp derived products, though these products still fall under the purview of the FDA.
Laboratory evidence indicated that cannabidiol may reduce THC clearance, increasing plasma concentrations which may raise THC availability to receptors and enhance its effect in a dose-dependent manner. In vitro, cannabidiol inhibited receptors affecting the activity of voltage-dependent sodium and potassium channels, which may affect neural activity. A small clinical trial reported that CBD partially inhibited the CYP2C-catalyzed hydroxylation of THC to 11-OH-THC.