“Cannabidiol (CBD), a major cannabinoid of hemp, does not bind to CB1 receptors and is therefore devoid of psychotomimetic properties. Under acidic conditions, CBD can be transformed to delta9-tetrahydrocannabinol (THC) and other cannabinoids. It has been argued that this may occur also after oral administration in humans. However, the experimental conversion of CBD to THC and delta8-THC in simulated gastric fluid (SGF) is a highly artificial approach that deviates significantly from physiological conditions in the stomach; therefore, SGF does not allow an extrapolation to in vivo conditions.
Unsurprisingly, the conversion of oral CBD to THC and its metabolites has not been observed to occur in vivo, even after high doses of oral CBD. In addition, the typical spectrum of side effects of THC, or of the very similar synthetic cannabinoid nabilone, as listed in the official Summary of Product Characteristics (e.g., dizziness, euphoria/high, thinking abnormal/concentration difficulties, nausea, tachycardia) has not been observed after treatment with CBD in double-blind, randomized, controlled clinical trials. In conclusion, the conversion of CBD to THC in SGF seems to be an in vitro artifact.
Over 40 years of research on CBD does not suggest a conversion of CBD to delta9-THC and/or other cannabinoids in vivo after oral administration. Such transformation occurs under artificial conditions, but is without any relevance for an oral therapy with CBD.” http://online.liebertpub.com/doi/full/10.1089/can.2017.0009?_ga=2.206725530.884504339.1500032065-2115951543.1500032065#
“Cannabidiol Does Not Convert to THC In Vivo. Although CBD Can Be Transformed to THC Under Acidic Conditions, the Conversion of Oral CBD Doesn’t Occur In Vivo” http://www.genengnews.com/gen-exclusives/cannabidiol-does-not-convert-to-thc-iin-vivoi/77900938