Determination of cannabinoids in hair of CBD rich extracts consumers using gas chromatography with tandem mass spectrometry (GC/MS-MS).

Medical cannabis is becoming increasingly popular for many different ailments and improvement of general well-being. Particularly CBD-rich extracts are easily available via online pharmacies, health stores or directly from producers. However, almost all of the extracts contain small amounts of THC. Thus, in case of continuous or heavy use of CBD rich cannabis, THC concentrations in hair may rise above accepted legal limits. In our study, we investigated THC, CBN and CBD in hair samples from regular CBD rich cannabis users. The goals were to determine levels of the cannabinoids in hair and to evaluate a possible correlation between regular CBD intake and CBD levels in hair. All participants consumed cannabis extracts from the same producer. It contained CBD at different concentrations and small amounts of THC with a CBD/THC concentration ratio of 30. The self-declared CBD dosage ranged from 4 to 128mg CBD/day, corresponding to a daily THC intake of 0.1 to 4.3mg. After extraction and derivatization, hair samples were analysed using a validated GC/MS-MS method. CBD concentrations ranged from 10 to 325pg/mg of hair, but no significant correlation was observed between CBD concentrations and the daily dose. THC was detected in one sample only at a concentration below our cut-off, whereas CBN was not detected. In this study, we showed that even after repeated consumption of CBD-rich cannabis extracts in medium to high doses, consumers are generally tested negative for THC in hair.