Ever since, recreational drug testing is being conducted in a growing number of countries. Recreational drug testing services became available in the 1990s . Another strategy could entail the introduction of specialized drug checking services for this user community. Therefore, it is of great importance that clinicians, politicians and law-makers are aware of this considerable individual and public health threat, given the significant negative long-term health impact of AAS misuse and exposure to fake AAS. Furthermore, due to punitive laws, stigma, and inexperience of health care professionals, this user population is widely unaccessed. Furthermore, first time use of anabolic agents has already been described in high-school age adolescents . Updated numbers are urgently needed, as the popularity of these substances is described to have increased, i.e. in the UK it is estimated that AAS popularity has doubled within the 10 years to 2018 . The analysis for substandard substances comes with some challenges. In two articles, the authors analyzed mixed samples, but the proportion of AAS was above 75%, as described in the inclusion criteria published in the study protocol 34–36. In 17 articles we were able to extract samples that exclusively analyzed anabolic agents (WADA class S1). AC provided methodological expertise on biochemical analysis of the samples. This may have resulted in some bias of the studies included and a bias in our statistical summary and conclusions. One strategy could entail the controlled use and availability of these substances through proper health channels. Different harm reduction strategies could be employed to limit this user community from either getting in contact with fake AAS from the black market or to promote safer use and informed decision making. There is a large and increasing number of individuals who are possibly exposed to these fake AAS on the black market. Graham and colleagues demonstrated contamination with bacterial skin commensals during microbiological analysis of their samples. We demonstrate that on some occasions completely different pharmaceuticals were identified during the analysis, such as quinine (antimalarial drug), instead of AAS. This often leads to products that may be subpar, with issues such as powdery tablets or inconsistently filled multi-dose vials—signs of poor manufacturing practices. Quality control is completely in the hands of the people operating the labs without any oversight. Most of these operations will buy bulk powders from China and manufacture the products in their basement or garage in pots and pans; the whole operation is just risky and unpredictable. Products from these labs carry a high risk of containing impurities and contaminants. In 2014, Sagoe and colleagues estimated, in a systematic review, that the global lifetime prevalence of AAS use was as high as 3.3% in the general population, but may be as high as 6.4% for males and 1.6% for females . We demonstrate that foreign shipments of fake AAS over the past years may have increased significantly, thus the negative consequences on public health may be substantial. In addition, recreational drugs are also commonly consumed. This is especially concerning when those substances are injected into the muscle as it poses a risk of forming abscesses in the muscle and skin necrosis 36, 61. Products from clandestine laboratories do not go through microbiological quality control, which can lead to sterility issues and microbiological contamination of injectables. This can, taken unknowingly, lead to substantial drug-related side effects. The counterfeit drug market can affect all drugs and is estimated to be a multimillion dollar business . This provides the perfect foundation for a counterfeit drug market for all IPEDs. Eligible articles were extracted; quality appraisal was done using the ToxRTool for in-vitro studies. Primary outcomes were proportions of counterfeit or substandard AAS. Studies were included if they report on qualitative and/or quantitative analytical findings of AAS from the black market. The pooled proportions for primary outcomes and corresponding 95% confidence interval (CI) were calculated using a random-effect model, using the procedure for meta-analysis of single proportions "metaprop" from the library "meta", provided in R software for statistical computing. We further classified compounds according to the suggested classification of Neves , and Weber and colleagues with adaptions into "original", "substandard" and "counterfeit". • peer-reviewed original articles with full-text available Quality assessment for bias of analytical studies was conducted using the ToxRtool for in-vitro studies and was assessed by two reviewers (RM and PB) independently. We conducted a systematic review and meta-analysis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 (PRISMA) statement . To our knowledge, this is the first systematic literature review analyzing fake black-market AAS within the published literature. Trust in the seller is described as the key criterion for protection against counterfeit drugs .
