 
        This means that supplement manufacturers do not need prior approval from the MHRA before producing or selling their product and there is no requirement for supplements to be licensed. Further, supplements sold in the UK have not been subjected to the same scientific scrutiny as medicines and are not as strictly regulated.
Most importantly, supplements are not tested on product safety, quality and efficacy before they hit the shelves because there is no legal obligation for supplement manufacturers to take part in testing products.
Contamination
There is a growing body of research which indicates that many supplements sold in the UK may be contaminated with “banned” and often dangerous substances. A 2004 study, for instance, tested 634 supplements purchased in 13 countries from 215 different suppliers. Of the 634 samples analysed, 94 (14.8%) contained anabolic androgenic steroids (AAS), 18.8% of which were purchased in the UK. Further, a study in 2008 found that 10% of supplements and weight loss products purchased and tested in the UK were contaminated with steroids and/or stimulants. A more recent study tested 24 products sold in fitness shops in the UK that were suspected of containing AAS. Of the 24 products tested, 23 contained steroids including known anabolic agents. 
        Chronic use
The contamination of nutritional supplements is a risk to both public health and to athletes unaware that their legal supplements may contain substances banned by anti-doping authorities. The chronic consumption of such products could unwittingly expose users to significant health risks. For instance AAS such as testosterone may have particular side effects, from acne and lowered HDL to testicular atrophy and liver damage, to name a few.Where supplements are mislabelled or contain fillers, users may be subject to mild to severe reactions as a result of unlisted ingredients. Even where supplements contain no “harmful” ingredients, replacing advertised supplements with something other than what is claimed on the label, or making false claims surrounding the quality of the product, is tantamount to consumer fraud.
In the case of athletes, using contaminated supplements may result in a positive doping tests, having detrimental effects on their athletic career. A review of the available data indicates that between 40–70% of athletes use supplements and that between 10 and 15% of supplements may contain prohibited substances. Consequently, there is considerable risk of accidental or inadvertent doping through the consumption of supplements. In fact in 2012, the UK Anti-Doping (UKAD) reported that approximately 44% of positive dope tests in the UK were thought to have been the consequence of prohibited substances in supplements.
Minimising risk
More stringent regulation and oversight is clearly necessary to ensure the safety and quality of supplements for everyday consumers and athletes alike. But supplement users can employ strategies to minimise their risk. 
        If individuals decide to use legal supplements, they should ensure they choose products that contain only the substance they require – and purchase supplements from a reputable manufacturer. Athletes, in particular, have to take care by choosing supplements that have been rigorously tested and approved prior to sale as they take personal responsibility for the risks that supplements carry.
None of this guarantees protection from possible contaminations and rather than placing responsibility for safety in the hands of often naive supplement consumers, the state should take on a greater role in the regulation of the industry.
