An Analysis of Over-the-Counter Cannabidiol Products in the United Kingdom

Abstract

Introduction: Over-the-counter cannabidiol (CBD) products have seen unprecedented recent growth in the United Kingdom. However, analysis of these predominantly unregulated products from other countries tells us that they are often mislabeled or contain unlabeled and potentially dangerous chemicals. Thus, the aim of the present study was to analyze CBD oils available in the United Kingdom. Materials and Methods: Phytocannabinoids, residual solvent, and heavy metals were measured blinded in 29 widely available CBD products by an independent testing facility using high-performance liquid chromatography with diode-array detection for cannabinoids, Headspace-gas chromatography-flame ionization detector and gas chromatography-mass spectrometry for residual solvents, and inductively coupled plasma-mass spectrometry for heavy metals. Results: The mean advertised CBD content was 4.5%, and the actual mean measured CBD content of products was 3.2% (p=0.053, Mann-Whitney test). Only 11/29 (38%) products were within 10% of the advertised CBD content. Fifty five percent of products had measurable levels of the controlled substances Δ⁹-tetrahydrocannabinol (mean content 0.04%) or cannabinol (mean content 0.01%), as well as most other phytocannabinoid compounds including cannabidiolic acid (CBDA), cannabidivarin (CBDV), and cannabidivarin acid (CBDVA). Detectable levels of N-pentane, ethanol, isopropanol, heptane, lead, and arsenic were found in many of the CBD products, but these were within acceptable levels. Conclusions: As demonstrated in other countries, the quality of over-the-counter CBD products in the United Kingdom can be substandard, particularly with regard to CBD content, and often contains levels of controlled substances. We recommend that these products be more strictly regulated for consumer welfare.

Keywords: cannabidiol; over the counter; phytocannabinoid; quality.

FIG. 1.

CBD measurements in 29 commercially available CBD oils. Products were tested for CBD-derived compounds including CBD, CBDA, CBDV, and CBDA (A) and the actual versus the advertised mean content compared (Mann–Whitney test, B). (C) The % deviation of products compared with the advertised CBD content looking at CBD only and if all CBD compounds (CBD, CBDA, CBDV, and CBDVA) were considered. (D) The correlation of the advertised CBD with the total phytocannabinoid content (red), total CBD content (green), or CBD only content (black). Data are presented as scatterplots with mean±SD. CBD, cannabidiol; CBDA, cannabidiolic acid; CBDV, cannabidivarin; CBDVA, cannabidivarin acid; SD, standard deviation.

FIG. 2.

Phytocannabinoid measurements in 29 commercially available CBD oils. Products were tested for phytocannabinoids other than CBD including the controlled phytocannabinoids, THC or CBN. Data are presented as a scatterplot with mean±SD. CBN, cannabinol; THC, Δ-tetrahydrocannabinol.

FIG. 3.

Solvent (A) and heavy metal (B) content (expressed in μg/mL or ppm) in the 29 commercially available CBD oils analyzed in this study. Data are presented as scatterplots with mean±SD.