A Warning against the Negligent Use of Cannabidiol in Professional and Amateur Athletes
2. Considerations for the Use of CBD Products in Athletes
- Medicinal products—if available—are to be preferred over food supplements or other product categories such as cosmetics or air fresheners, because medicinal products are typically better purified and more strictly controlled. The use of medicinal products on prescription by sport medicine specialists also has the advantage of medical surveillance for adverse effects such as liver toxicity .
- For products marketed as food or nutritional supplements, the following special scrutiny is required:
- Products labelled as “full spectrum extracts” contain—besides CBD—undefined concentrations of other cannabinoids. Therefore, according to the regulations of the WADA (prohibited list)  the use of such products is, in general, illegal. Athletes should neither use such products in competition nor during competition periods (due to the long window of detectability of 11-nor-9-carboxy-THC in urine).
- Producers should provide credible analytical proof for the claims about CBD content on the labels. Many studies of CBD products have detected considerable mislabeling of content [9,18,19,20,21]. Analytical reports on websites of CBD producers should therefore be critically questioned, specifically if they only provide “lower than” results or even THC-free claims but with comparably high limits of detection (such as only <0.2%). Limits of detection in the percentage range are not able to ensure the absence of THC in a magnitude that would also exclude THC-positive urine tests. For example, the German target value to exclude any risk of THC in foods would be 150 µg/kg (0.000015%) [22,23,24], and only such a level would also exclude any risk of a positive drug test with certainty. Sensitive methods, such as combinations of gas or liquid chromatography with tandem mass spectrometry (MS/MS), are necessary for adequate quality control [13,25]. Methods with unspecific and insensitive detectors, such as flame-ionization detection (FID) are typically inadequate. Therefore, a careful interpretation of analytical reports is necessary, which is probably impossible for CBD consumers, who should consult experts if in doubt. To avoid the adverse effects of THC, the residual THC content in CBD products must be below the acute reference dose of the European Food Safety Authority (EFSA), which is 1 µg/kg bodyweight/day . The highest risk for residual THC comes from products not intended for human consumption, such as air fresheners or cosmetics, which may be used orally off-label.
- Good manufacturing practice would also include testing for residual solvents, contaminants and residues such as heavy metals, mycotoxins or pesticides.
- Mandatory labelling should be complete and correct (e.g., regarding ingredients, minimum durability, etc.).
- Claims about health- and disease-related effects are prohibited except in cases of approved medicinal products. If producers advertise effects such as cancer-prevention for food supplements, this seriously questions the trustworthiness of the producers, and means that they probably mislead the consumer about other things, such as absence of THC content as well.
- The safety of the long-term use of CBD is understudied and there are indications of some adverse effects including liver toxicity and an influence of male fertility . A risk-benefit analysis should carefully consider the possible, so far non-approved benefits of CBD for athletes  against its safety-profile.
Conflicts of Interest
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Lachenmeier, D.W.; Diel, P. A Warning against the Negligent Use of Cannabidiol in Professional and Amateur Athletes. Sports 2019, 7, 251. https://doi.org/10.3390/sports7120251
Lachenmeier DW, Diel P. A Warning against the Negligent Use of Cannabidiol in Professional and Amateur Athletes. Sports. 2019; 7(12):251. https://doi.org/10.3390/sports7120251Chicago/Turabian Style
Lachenmeier, Dirk W., and Patrick Diel. 2019. "A Warning against the Negligent Use of Cannabidiol in Professional and Amateur Athletes" Sports 7, no. 12: 251. https://doi.org/10.3390/sports7120251