Preliminary data on the potential for unintentional antidoping rule violations by permitted cannabidiol (CBD) use

Influence of short-term chronic oral cannabidiol application on muscle recovery and performance after an intensive training protocol - a randomized double-blind crossover study

BACKGROUND

Rapid regeneration after intense exercise is essential for competitive athletes. Based on this assumption, supplementation strategies, focusing on food supplements, are increasing to improve the recovery processes. One such supplement is cannabidiol (CBD) which is gaining more attention in competitive sports. However, the evidence is still lacking and there are no data available about the effect of a short-term chronic application.

METHODS

A three-arm double-blind cross-over study was conducted to determine the effects of two different CBD products on performance, muscle damage and inflammatory processes in well-trained athletes. In total 17 subjects took successfully part in this study. Each subject underwent the six-day, high-intensity training protocol three times. After each training session, each subject took either a placebo or a CBD product (60 mg of oil or solubilisate). Between the intervention phases, at least four weeks of washout period was conducted. Before and after the training protocols the performance capacity in countermovement jump (CMJ), back squat (BS), bench press (BP) and 1-mile run were measured and biomarkers for muscle damage (creatine kinase, myoglobin), inflammatory processes (interleukin 6 and 10) and immune cell activity (ratios of neutrophil granulocytes, lymphocytes and, platelets) were analyzed. For statistical analyses, the current version of R and a linear mixed model was used.

RESULTS

It could identify different effects of the training protocol depending on performance level (advanced or highly advanced athletes) (p < .05). Regardless of the performance level, muscle damage and a reduction in performance could be induced by the training protocol. Only CBD oil was associated with a reduction in myoglobin concentration (p < .05) in advanced athletes. Concerning immune activity, a significant decrease in platelets lymphocyte ratios was observed in advanced athletes after placebo treatment (p < .05). CBD oil application showed a slight inhibitory effect (p < .10). Moreover, the reduction in performance differs between the performance levels. A significant decrease in CMJ was observed in advanced athletes and a decreasing trend in BS was observed in highly advanced athletes after placebo treatment (p < 0.10). Both CBD products do not affect performance parameters. For inflammatory parameters, no effects were observed.

CONCLUSION

It was found that the performance level of the subjects was a decisive factor and that they responded differently to the training protocol and the CBD application. However, no clear effects of either CBD product were found and further research is needed to identify the long-term effects of CBD application.

In vivo comparative study of hemp straw exposure and cannabidiol oil administration in horse urine

The non-psychoactive cannabinoids cannabidiol (CBD) and cannabidiolic acid (CBDA) are available on the market in different forms, mostly for their anti-inflammatory and potential analgesic properties. These substances are prohibited during equine competitions. CBD and CBDA are naturally present in hemp straw, commonly used as a bedding substitute for wheat straw. Unfortunately, horses can eat it, which therefore could lead to a possible risk of positive findings for CBD/CBDA in biological samples after doping control tests. The goals of this study were, first, to provide recommendations on the use of hemp straw before competition and, second, to assess if discrimination between hemp bedding exposure and CBD oil administration is possible. Several CBD equine in vivo studies have been conducted, including one on hemp straw used as bedding and one after administration of CBD oil by topical and sublingual routes. In hemp straw, CBDA was detected in higher quantities than CBD, and other cannabinoids have been observed. After hemp straw exposure, CBDA was also detected in higher quantities than CBD in all urine samples. It appeared that hemp straw should not be used as bedding for equine competition except if a delay of at least 48 h is respected. Regarding the CBD oil product analysis, CBD was the main compound detected. After administration, 7-hydroxy CBD was identified in the urine. In conclusion, based on these data, we highlighted that it could be possible to discriminate the exposure of a horse to hemp straw from an administration of a CBD oil product thanks to the main presence of CBDA.

Cannabigerol (CBG) signal enhancement in its analysis by gas chromatography coupled with tandem mass spectrometry

PURPOSE

According to recent reports, cannabigerol (CBG) concentration level in blood and body fluids may have forensic utility as a highly specific albeit insensitive biomarker of recent cannabis smoking. While the analytical sensitivity of cannabidiol (CBD), Δ9-tetrahydrocannabinol (Δ9-THC), cannabichromene (CBC) or cannabinol (CBN) estimation by gas chromatography-mass spectrometry (GC-MS) is similar and sufficiently high, it is exceptionally low in the case of CBG (ca. 25 times lower than for the other mentioned cannabinoids). The purpose of this study is to explain the reasons for the extremely low analytical sensitivity of GC-MS in estimating CBG and to present possible ways of its improvement.

METHODS

Nuclear magnetic resonance (NMR) data and GC-MS responses to CBG and its various derivatization and transformation products were studied.

RESULTS

The validation data of individual derivatives of CBG and its transformation products were established. CBG silylation/acylation or hydration allows to decrease LOD about 3 times, whereas the formation of pyranic CBG derivative leads to 10-times decrease of LOD. The paper enriches the literature of the subject by providing MS and NMR spectra, not published so far, for derivatives of CBG and its transformation products. The most likely cause of low GC-MS response to CBG is also presented.

CONCLUSIONS

The presented results shows that although the signal increase of CBG can be obtained through its derivatization by silylation and/or acylation, the greatest increase is observed in the case of its cyclization to the pyranic CBG form during the sample preparation process. The CBG cyclization procedure is very simple and workable in estimating this cannabinoid in blood/plasma samples.

Application of gas chromatography in the analysis of phytocannabinoids: An update (2020-2023)

INTRODUCTION

Cannabinoids are a group of compounds that bind to cannabinoid receptors. They possess pharmacological properties like that of the plant Cannabis sativa. Gas chromatography (GC) is one of the popular chromatographic techniques that has been routinely used in the analysis of cannabinoids in different matrices.

OBJECTIVE

The article aims to review the literature on the application of GC-based analytical methods for the analysis of phytocannabinoids published during the period from January 2020 to August 2023.

METHODOLOGY

A thorough literature search was conducted using different databases, like Web of Knowledge, PubMed, Google Scholar, and other relevant published materials including published books. The keywords used, in various combinations, with cannabinoids being present in all combinations, in the search were cannabinoids, Cannabis sativa, marijuana, analysis, GC, quantitative, qualitative, and quality control. From the search results, only the publications that incorporate the GC analysis of phytocannabinoids were reviewed, and papers on synthetic cannabinoids were excluded.

RESULTS

Since the publication of the review article on GC analysis of phytocannabinoids in early 2020, several GC-based methods for the analysis of phytocannabinoids have appeared in the literature. While simple 1D GC-mass spectrometry (MS) and GC-flame ionisation detector (FID) methods are still quite common in phytocannabinoids analysis, 2D GC-MS and GC-MS/MS are increasingly becoming popular, as these techniques offer more useful data for identification and quantification of phytocannabinoids in various matrices. The use of automation in sample preparation and the utilisation of mathematical and computational models for optimisation of different protocols have become a norm in phytocannabinoids analysis. Pre-analyses have been found to incorporate different derivatisation techniques and environmentally friendly extraction protocols.

CONCLUSIONS

GC-based analysis of phytocannabinoids, especially using GC-MS, remains one of the most preferred methods for the analysis of these compounds. New derivatisation methods, ionisation techniques, mathematical models, and computational approaches for method optimisation have been introduced.

Pharmacokinetic modelling of orally administered cannabidiol and implications for medication control in horses

Cannabidiol (CBD) products gain increasing popularity amongst animal owners and veterinarians as an alternative remedy for treatment of stress, inflammation or pain in horses. Whilst the use of cannabinoids is banned in equine sports, there is limited information available concerning CBD detection times in blood or urine. The aim of this study was to determine the pharmacokinetic properties of CBD following oral administration in the horse to assist doping control laboratories with interpreting CBD analytical results. Part 1: dose escalation study: Single oral administration of three escalating doses of CBD paste (0.2 mg/kg, n = 3 horses; 1 mg/kg, n = 3; 3 mg/kg, n = 5) with >7 days wash-out periods in between. Part 2: multiple dose study: oral administration of CBD paste (3 mg/kg, n = 6) twice daily for 15 days. Multiple blood and urine samples were collected daily throughout both studies. Following study part 2, blood and urine samples were collected for 2 weeks to observe the elimination phase. Concentrations of CBD, its metabolites and further cannabinoids were evaluated using gas-chromatography/tandem-mass-spectrometry. Pharmacokinetic parameters were assessed via two approaches: population pharmacokinetic analysis using a nonlinear mixed-effects model and non-compartmental analysis. AUC0-12 h and Cmax were tested for dose proportionality. During the elimination phase, the CBD steady-state urine to serum concentration ratio (Rss) was calculated. Oral CBD medication was well-tolerated in horses. Based on population pharmacokinetics, a three-compartment model with zero-order absorption most accurately described the pharmacokinetic properties of CBD. High volumes of distribution into peripheral compartments and high concentrations of 7-carboxy-CBD were observed in serum. Non-compartmental analysis identified a Cmax of 12.17 ± 2.08 ng/mL after single administration of CBD (dose: 3 mg/kg). AUC0-12 h showed dose proportionality, increase for Cmax leveled off at higher doses. Following multiple doses, the CBD terminal half-life was 161.29 ± 43.65 h in serum. Rss was 4.45 ± 1.04. CBD is extensively metabolized and shows high volumes of tissue distribution with a resulting extended elimination phase. Further investigation of the potential calming and anti-inflammatory effects of CBD are required to determine cut-off values for medication control using the calculated Rss.

Cannabidiol for musculoskeletal regenerative medicine

Chronic musculoskeletal (MSK) pain is one of the most prevalent causes, which lead patients to a physician's office. The most common disorders affecting MSK structures are osteoarthritis, rheumatoid arthritis, back pain, and myofascial pain syndrome, which are all responsible for major pain and physical disability. Although there are many known management strategies currently in practice, phytotherapeutic compounds have recently begun to rise in the medical community, especially cannabidiol (CBD). This natural, non-intoxicating molecule derived from the cannabis plant has shown interesting results in many preclinical studies and some clinical settings. CBD plays vital roles in human health that go well beyond the classic immunomodulatory, anti-inflammatory, and antinociceptive properties. Recent studies demonstrated that CBD also improves cell proliferation and migration, especially in mesenchymal stem cells (MSCs). The foremost objective of this review article is to discuss the therapeutic potential of CBD in the context of MSK regenerative medicine. Numerous studies listed in the literature indicate that CBD possesses a significant capacity to modulate mammalian tissue to attenuate and reverse the notorious hallmarks of chronic musculoskeletal disorders (MSDs). The most of the research included in this review report common findings like immunomodulation and stimulation of cell activity associated with tissue regeneration, especially in human MSCs. CBD is considered safe and well tolerated as no serious adverse effects were reported. CBD promotes many positive effects which can manage detrimental alterations brought on by chronic MSDs. Since the application of CBD for MSK health is still undergoing expansion, additional randomized clinical trials are warranted to further clarify its efficacy and to understand its cellular mechanisms.

Risk of unintentional antidoping rule violations by consumption of hemp products

Consumption of hemp products is continuously growing, with an expanding scope of applications. Suppliers operate through different distribution channels, but the Internet is a major retail platform. Hemp products are prepared from cannabis plants and, therefore, might contain a variety of different natural cannabinoids. According to the regulations of the World Anti-Doping Agency, all natural and synthetic cannabinoids are prohibited in-competition, with the explicit exemption of cannabidiol. Therefore, an investigation of 23 hemp products for the presence of cannabinoids was performed to determine the likelihood of unintentional violations of anti-doping regulations. An assay for the detection of 16 cannabinoids in nutritional supplements was developed and validated. The sample preparation consisted of QuEChERS extraction, trimethylsilylation, and analysis by gas chromatography/tandem mass spectrometry. All 23 commercially available hemp products were analyzed, and assay characteristics such as selectivity, limit of detection, limit of identification, limit of quantification, linearity, imprecision, recovery, and accuracy were determined. Twenty of 23 hemp products included a variety of cannabinoids at, occasionally, substantial concentrations, with four products covering the entire spectrum of tested cannabinoids. An ethics committee-approved single-dose administration study was conducted with the commercially available hemp products, investigating the presence of 16 cannabinoids in urine collected pre- and post-consumption. Variable patterns of cannabinoids or their metabolites in urine were observed. In 30% of the urine samples collected 8 h after ingestion, the presence of a prohibited cannabinoid would have resulted in an unintentional violation of anti-doping regulations.

Are adverse effects of cannabidiol (CBD) products caused by tetrahydrocannabinol (THC) contamination?

Cannabidiol (CBD)-containing products are widely marketed as over the counter products, mostly as food supplements. Adverse effects reported in anecdotal consumer reports or during clinical studies were first assumed to be due to hydrolytic conversion of CBD to psychotropic Δ ⁹-tetrahydrocannabinol (Δ ⁹-THC) in the stomach after oral consumption. However, research of pure CBD solutions stored in simulated gastric juice or subjected to various storage conditions such as heat and light with specific liquid chromatographic/tandem mass spectrometric (LC/MS/MS) and ultra-high pressure liquid chromatographic/quadrupole time-of-flight mass spectrometric (UPLC-QTOF) analyses was unable to confirm THC formation. Another hypothesis for the adverse effects of CBD products may be residual Δ ⁹-THC concentrations in the products as contamination, because most of them are based on hemp extracts containing the full spectrum of cannabinoids besides CBD. Analyses of 293 food products of the German market (mostly CBD oils) confirmed this hypothesis: 28 products (10%) contained Δ ⁹-THC above the lowest observed adverse effect level (2.5 mg/day). Hence, it may be assumed that the adverse effects of some commercial CBD products are based on a low-dose effect of Δ ⁹-THC, with the safety of CBD itself currently being unclear with significant uncertainties regarding possible liver and reproductive toxicity. The safety, efficacy and purity of commercial CBD products is highly questionable, and all of the products in our sample collection showed various non-conformities to European food law such as unsafe Δ ⁹-THC levels, hemp extracts or CBD isolates as non-approved novel food ingredients, non-approved health claims, and deficits in mandatory food labelling requirements. In view of the growing market for such lifestyle products, the effectiveness of the instrument of food business operators' own responsibility for product safety and regulatory compliance must obviously be challenged, and a strong regulatory framework for hemp products needs to be devised.

Cannabidiol (CBD) product contamination: Quantitative analysis of Δ9-tetrahydrocannabinol (Δ9-THC) concentrations found in commercially available CBD products

BACKGROUND

Regulation has not kept pace with the growth of the hemp-derived CBD market. We have evaluated the risk of Δ⁹-tetrahydrocannabinol (Δ⁹-THC) contamination in 80 unregulated products with comparison to a regulated control, Epidiolex®.

METHODS

Local and national brands of hemp-derived oil products were purchased online and from local retailers in central Kentucky (which carry both national and local brands). These were extracted by solvent extraction and quantified by liquid-chromatography tandem mass-spectrometry (LC-MS/MS) using a validated method.

RESULTS

Of the 80 unregulated products and Epidiolex®, Δ⁹-THC was detected above the limit of quantification (LOQ = 0.005 mg/mL) of the assay in 52 samples, ranging from 0.008 mg/mL to 2.071 mg/mL. Twenty-one of the products tested were labelled as "THC-Free", and 5 of these products contained detectable levels of Δ⁹-THC ranging from 0.015 mg/mL to 0.656 mg/mL.

CONCLUSIONS

Consumers are taking hemp-derived CBD products without understanding the risks of unintentional consumption of Δ⁹-THC. This accidental use of Δ⁹-THC could have adverse effects on health and safety as well as potential legal consequences (e.g., child custody, impaired driving), as Δ⁹-THC drug test findings could impact employment, military, and sport eligibility status.

Quantitative determination of five cannabinoids in blood and urine by gas chromatography tandem mass spectrometry applying automated on-line solid phase extraction

Cannabis is the most frequently consumed illegal substance worldwide. More recently, an increasing number of legal cannabis products low in psychoactive Δ⁹‐tetrahydrocannabinol (THC) but high in non‐intoxicating cannabidiol (CBD) are being more widely consumed. While the detection and quantification of THC and its metabolites in biological matrices is an important forensic‐toxicological task, additional detection of CBD is also important, for example, when examining the plausibility of consumer's statements. This report describes the method validation for the quantitative determination of THC and its two major metabolites, 11‐hydroxy‐THC (OH‐THC) and 11‐nor‐9‐carboxy‐THC (THC‐COOH), as well as CBD and cannabinol (CBN) in whole blood and urine. The method employs automated on‐line solid phase extraction coupled to gas chromatography tandem mass spectrometry (GC–MS/MS). The method was fully validated according to guidelines of the Swiss Society of Legal Medicine (SGRM) and the Society of Toxicological and Forensic Chemistry (GTFCh). The method fulfilled the validation criteria regarding analytical limits, accuracy and precision, extraction efficacy, and sample stability. The limits of detection (LODs) in whole blood and urine were 0.15 ng/mL for THC, OH‐THC and CBD, 0.1 ng/mL for CBN, and 1.0 ng/mL for THC‐COOH. The limits of quantification (LOQ) in whole blood and urine were 0.3 ng/mL for THC, OH‐THC and CBD, 0.2 ng/mL for CBN, and 3.0 ng/mL for THC‐COOH. The fully validated and automated method allows sensitive and robust measurement of cannabinoids in whole blood and urine. Detection of CBD provides additional information regarding consumed products.

Annual banned-substance review: Analytical approaches in human sports drug testing 2020/2021

Most core areas of anti-doping research exploit and rely on analytical chemistry, applied to studies aiming at further improving the test methods' analytical sensitivity, the assays' comprehensiveness, the interpretation of metabolic profiles and patterns, but also at facilitating the differentiation of natural/endogenous substances from structurally identical but synthetically derived compounds and comprehending the athlete's exposome. Further, a continuously growing number of advantages of complementary matrices such as dried blood spots have been identified and transferred from research to sports drug testing routine applications, with an overall gain of valuable additions to the anti-doping field. In this edition of the annual banned-substance review, literature on recent developments in anti-doping published between October 2020 and September 2021 is summarized and discussed, particularly focusing on human doping controls and potential applications of new testing strategies to substances and methods of doping specified in the World Anti-Doping Agency's 2021 Prohibited List.

Sports drug testing and the athletes' exposome

Similar to the general population, elite athletes are exposed to a complex set of environmental factors including chemicals and radiation and also biological and physical stressors, which constitute an exposome that is, unlike for the general population, subjected to specific scrutiny for athletes due to applicable antidoping regulations and associated (frequent) routine doping controls. Hence, investigations into the athlete's exposome and how to distinguish between deliberate drug use and different contamination scenarios has become a central topic of antidoping research, as a delicate balance is to be managed between the vital and continually evolving developments of sensitive analytical techniques on the one hand, and the risk of the athletes' exposome potentially causing adverse analytical findings on the other.

Emergence of the less common cannabinoid Δ8 -Tetrahydrocannabinol in a doping sample

Δ⁸ -Tetrahydrocannabinol (Δ⁸ -THC) as isomer of the well-known Δ⁹ -THC has a similar mode of action, and the potency was estimated to be two thirds compared with Δ⁹ -THC. Content of Δ⁸ -THC in plant material is low, but formulations containing Δ⁸ -THC in high concentrations are gaining popularity. Δ⁸ -THC is to be regarded as prohibited substance according to the Prohibited List of the World Anti-Doping Agency (WADA). Contradictory results between initial testing procedure and confirmatory quantitation for 11-Nor-9-carboxy-Δ⁹ -tetrahydrocannabinol (Δ⁹ -THC-COOH) of a doping control sample gave rise for follow-up testing procedures. After alkaline hydrolysis and liquid-liquid extraction, the sample was analyzed by high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) using isocratic elution instead of gradient elution, which is used for standard procedure. Isocratic elution resulted in two peaks instead of one using gradient elution. Both peaks showed same fragmentation. Using certified reference materials, one peak could be assigned to Δ⁹ -THC-COOH and the other one with higher intensity to the less common 11-Nor-9-carboxy-Δ⁸ -Tetrahydrocannabinol (Δ⁸ -THC-COOH) in a concentration of approximately 1200 ng/ml. As complementary method, gas chromatography tandem mass spectrometry (GC-MS/MS) can also be used for identification. Here Δ⁸ - and Δ⁹ -THC-COOH can be distinguished by chromatography and by fragmentation. Additional investigations of doping control samples containing Δ⁹ -THC-COOH revealed the simultaneous presence of Δ⁸ -THC-COOH in low concentrations (0.22-8.91 ng/ml) presumably due to plant origin. Percentage of Δ⁸ -THC-COOH varies from 0.05 to 2.83%. In vitro experiments using human liver microsomes showed that Δ⁸ -THC is metabolized in the same way as Δ⁹ -THC.

Cases reports: Unintended anti-doping rule violation after dorzolamide use several months prior to a doping control

The use of specific medicine up to several months before a doping control is not be reported on the doping control form, while the drug could then still be detectable in urine in case of a very slow elimination. It may lead to a positive test result. For example, dorzolamide, a carbonic anhydrase inhibitor for topical ophthalmic application, has a very slow elimination rate via the renal route (half-life > 4 months). This substance can be a source of unintended anti-doping rule violations.

Potential Role of Cannabidiol on Sports Recovery: A Narrative Review

The use of cannabidiol (CBD) among athletes is becoming extensive and frequent. This could be due to the elimination of CBD from the list of prohibited substances by federations and international institutions of sport. The legalization and resulting production, and commercialization of CBD, could increase its intake in sports professionals. This commercialization of cannabinoids has fueled a race to study their properties, benefits, and risks for health and performance in athletes. Although there is evidence that suggests some beneficial properties such as anxiolytics, antidepressants, anti-inflammatory, and antioxidants among others, the evidence presented so far is neither clear nor conclusive. There are significant gaps in knowledge of the physiological pathways that explain the role of CBD in sports performance. This mini-review examines evidence suggesting that CBD has the potential to be used as a part of the strategies to recover from fatigue and muscle damage related to physical and cognitive exertion in sports.

Are adverse effects of cannabidiol (CBD) products caused by tetrahydrocannabinol (THC) contamination?

Cannabidiol (CBD)-containing products are widely marketed as over the counter products, mostly as food supplements. Adverse effects reported in anecdotal consumer reports or during clinical studies were first assumed to be due to hydrolytic conversion of CBD to psychotropic Δ ⁹-tetrahydrocannabinol (Δ ⁹-THC) in the stomach after oral consumption. However, research of pure CBD solutions stored in simulated gastric juice or subjected to various storage conditions such as heat and light with specific liquid chromatographic/tandem mass spectrometric (LC/MS/MS) and ultra-high pressure liquid chromatographic/quadrupole time-of-flight mass spectrometric (UPLC-QTOF) analyses was unable to confirm THC formation. Another hypothesis for the  adverse effects of CBD products may be residual Δ ⁹-THC concentrations in the products as contamination, because most of them are based on hemp extracts containing the full spectrum of cannabinoids besides CBD. Analyses of 181 food products of the German market (mostly CBD oils) confirmed this hypothesis: 21 products (12%) contained Δ ⁹-THC above the lowest observed adverse effect level (2.5 mg/day). Inversely, CBD was present in the products below the no observed adverse effect level. Hence, it may be assumed that the adverse effects of some commercial CBD products are based on a low-dose effect of Δ ⁹-THC and not due to effects of CBD itself. The safety, efficacy and purity of commercial CBD products is highly questionable, and all of the products in our sample collection showed various non-conformities to European food law such as unsafe Δ ⁹-THC levels, hemp extracts or CBD isolates as non-approved novel food ingredients, non-approved health claims, and deficits in mandatory food labelling requirements. In view of the growing market for such lifestyle products, the effectiveness of the instrument of food business operators' own responsibility for product safety and regulatory compliance must obviously be challenged, and a strong regulatory framework for hemp products needs to be devised.

Are adverse effects of cannabidiol (CBD) products caused by tetrahydrocannabinol (THC) contamination?

Cannabidiol (CBD)-containing products are widely marketed as over the counter products, mostly as food supplements. Adverse effects reported in anecdotal consumer reports or during clinical studies were first assumed to be due to hydrolytic conversion of CBD to psychotropic Δ ⁹-tetrahydrocannabinol (Δ ⁹-THC) in the stomach after oral consumption. However, research of pure CBD solutions stored in simulated gastric juice or subjected to various storage conditions such as heat and light with specific liquid chromatographic/tandem mass spectrometric (LC/MS/MS) and ultra-high pressure liquid chromatographic/quadrupole time-of-flight mass spectrometric (UPLC-QTOF) analyses was unable to confirm THC formation. Another hypothesis for the  adverse effects of CBD products may be residual Δ ⁹-THC concentrations in the products as contamination, because most of them are based on hemp extracts containing the full spectrum of cannabinoids besides CBD. Analyses of 181 food products of the German market (mostly CBD oils) confirmed this hypothesis: 21 products (12%) contained Δ ⁹-THC above the lowest observed adverse effect level (2.5 mg/day). Inversely, CBD was present in the products below the no observed adverse effect level. Hence, it may be assumed that the adverse effects of some commercial CBD products are based on a low-dose effect of Δ ⁹-THC and not due to effects of CBD itself. The safety, efficacy and purity of commercial CBD products is highly questionable, and all of the products in our sample collection showed various non-conformities to European food law such as unsafe Δ ⁹-THC levels, hemp extracts or CBD isolates as non-approved novel food ingredients, non-approved health claims, and deficits in mandatory food labelling requirements. In view of the growing market for such lifestyle products, the effectiveness of the instrument of food business operators' own responsibility for product safety and regulatory compliance must obviously be challenged, and a strong regulatory framework for hemp products needs to be devised.

Are adverse effects of cannabidiol (CBD) products caused by tetrahydrocannabinol (THC) contamination?

Cannabidiol (CBD)-containing products are widely marketed as over the counter products, mostly as food supplements. Adverse effects reported in anecdotal consumer reports or during clinical studies were first assumed to be due to hydrolytic conversion of CBD to psychotropic Δ ⁹-tetrahydrocannabinol (Δ ⁹-THC) in the stomach after oral consumption. However, research of pure CBD solutions stored in simulated gastric juice or subjected to various storage conditions such as heat and light with specific liquid chromatographic/tandem mass spectrometric (LC/MS/MS) and ultra-high pressure liquid chromatographic/quadrupole time-of-flight mass spectrometric (UPLC-QTOF) analyses was unable to confirm THC formation. Another hypothesis for the  adverse effects of CBD products may be residual Δ ⁹-THC concentrations in the products as contamination, because most of them are based on hemp extracts containing the full spectrum of cannabinoids besides CBD. Analyses of 181 food products of the German market (mostly CBD oils) confirmed this hypothesis: 21 products (12%) contained Δ ⁹-THC above the lowest observed adverse effect level (2.5 mg/day). Inversely, CBD was present in the products below the no observed adverse effect level. Hence, it may be assumed that the adverse effects of some commercial CBD products are based on a low-dose effect of Δ ⁹-THC and not due to effects of CBD itself. The safety, efficacy and purity of commercial CBD products is highly questionable, and all of the products in our sample collection showed various non-conformities to European food law such as unsafe Δ ⁹-THC levels, hemp extracts or CBD isolates as non-approved novel food ingredients, non-approved health claims, and deficits in mandatory food labelling requirements. In view of the growing market for such lifestyle products, the effectiveness of the instrument of food business operators' own responsibility for product safety and regulatory compliance must obviously be challenged, and a strong regulatory framework for hemp products needs to be devised.

Are adverse effects of cannabidiol (CBD) products caused by tetrahydrocannabinol (THC) contamination?

Cannabidiol (CBD)-containing products are widely marketed as over the counter products, mostly as food supplements. Adverse effects reported in anecdotal consumer reports or during clinical studies were first assumed to be due to acid-catalysed cyclization of CBD to psychotropic Δ ⁹tetrahydrocannabinol (Δ ⁹-THC) in the stomach after oral consumption. However, research of pure CBD solutions stored in simulated gastric juice or subjected to various storage conditions such as heat and light with specific liquid chromatographic/tandem mass spectrometric (LC/MS/MS) and ultra-high pressure liquid chromatographic/quadrupole time-of-flight mass spectrometric (UPLC-QTOF) analyses was unable to confirm THC formation. Another hypothesis for the adverse effects of CBD products may be residual Δ ⁹-THC concentrations in the products as contamination, because most of them are based on hemp extracts containing the full spectrum of cannabinoids besides CBD. Analyses of 362 hemp-based products of the German market (mostly CBD oils) confirmed this hypothesis: 39 products (11%) contained Δ ⁹-THC above the lowest observed adverse effect level (2.5 mg/day). Hence, it may be assumed that the adverse effects of some commercial CBD products are based on a low-dose effect of Δ ⁹-THC, with the safety of CBD itself currently being unclear with significant uncertainties regarding possible liver and reproductive toxicity. The safety, efficacy and purity of commercial CBD products is highly questionable, and all of the products in our sample collection showed various non-conformities to European food law such as unsafe Δ ⁹-THC levels, hemp extracts or CBD isolates as non-approved novel food ingredients, non-approved health claims, and deficits in mandatory food labelling requirements. In view of the growing market for such lifestyle products, the effectiveness of the instrument of food business operators' own responsibility for product safety and regulatory compliance must obviously be challenged, and a strong regulatory framework for hemp products needs to be devised.