Performance-Enhancing Drugs

Performance enhancement is of major importance in competitive and elite sports. Among the many methods  to  enhance  performance  in  sports,  such as  specialized  training  and  diet  regimes,  some athletes  seek  resort  to  performance-enhancing drugs  (PEDs).  Following  the  drug-related  death of  British  cyclist  Tom  Simpson  during  the  1967 Tour  de  France,  a  controversy  erupted  concerning the extent of drug use in sports and the health consequences  of  PEDs.  Today,  PEDs  are  broadly categorized into licit and illicit substances.

Illicit Performance-Enhancing Drugs

Since   1999,   the   World   Anti-Doping   Agency (WADA) has been regulating the use of illicit PEDs in sports. WADA annually issues an official list of prohibited  PEDs  and  regulates  drug  testing  and doping  control  procedures  in  collaboration  with national   anti-doping   organizations   (NADOs) across  the  world.  The  WADA  list  of  prohibited substances  distinguishes  between  substances  that are  banned  at  all  times  (both  inside  and  outside competition),   substances   prohibited   only   incompetition, as well as substances prohibited only in particular sports.

The  first  class  of  substances  (i.e.,  those  that are banned at all times) includes mainly anabolicandrogenic  steroids  (AAS),  such  as  human  hormone  testosterone  and  its  synthetic  or  natural derivatives (e.g., androstenediol, androstenedione, DHEA, and 7-keto DHEA). Other anabolic agents in  this  category  include  clenbuterol,  selective androgen  receptor  modulators  (SARMs),  peptide hormones, growth factors, and related substances (e.g., growth hormone, insulin-like growth factor-1 or  IGF-1,  and  erythropoiesis-stimulating  agents), beta-2 agonists, diuretics, and masking agents.

Prohibited  in-competition  substances  include stimulants, narcotics, cannabinoids, and glucocorticosteroids.  Additionally,  some  sporting  associations prohibit the use of alcohol and beta-blockers. Some  of  the  prohibited  stimulants  are  considered legal  if  they  are  found  in  relatively  low  concentrations in the athlete’s urine during drug testing. Also,  certain  prohibited  PEDs  are  allowed  to  be used  for  therapeutic  reasons  (Therapeutic  Use Exemptions  [TUEs])  and  under  medical  supervision. This related mostly to narcotic analgesics and other drugs that can have a therapeutic value.

Health Effects

The use and abuse of illicit PEDs, such as amphetamines  and  anabolic  steroids  cause  various  psychological  and  physical  health  symptoms,  such as  irritability,  aggressiveness,  violent  outbursts, depression,  suicidal  thoughts,  acne,  baldness, infertility  and  hypogonadism  (in  males  using AAS),  facial  hair  and  deepening  of  the  voice  (in females using AAS), heart disease, and liver toxicity. Prolonged or excessive use of growth hormone has also been linked to the development of cancer, disfigurement of facial bones, and sudden death.

Epidemiology of Illicit Performance-Enhancing Drugs in Professional and Amateur Sports

There is a plethora of known cases of elite athletes using or abusing illegal PEDs. However, establishing  reliable  and  accurate  prevalence  estimates  of illicit PEDs in sports represents a difficult task for numerous  reasons.  First,  the  use  of  biomedical testing  has  proven  problematic  in  relation  to  the high  financial  and  administrative  costs  involved. Second,  current  testing  procedures  often  fail  to detect newly introduced, prohibited PEDs. Third, biomedical testing can only be applied to a small subsample of the total population of elite athletes, thus some athletes may be regular users of prohibited  PEDs  but  escape  testing.  Finally,  self-reports of  drug  use  are  also  problematic,  as  elite  athletes  are  reluctant  to  disclose  drug  use  patterns. Therefore, while anecdotal evidence suggests that doping  in  elite  sports  may  be  more  than  50%, official reports only support that the prevalence of illicit PEDs range from 5% to 10%. Clearly, there is still a great deal of work to be done concerning the epidemiology of illicit PEDs in sports.

Notably, several studies indicate that the use of illicit  PEDs  is  not  limited  to  competitive  sports. Rather,  illicit  PEDs  are  also  used  in  nonprofessional  sports.  Amateur  athletes  and  adolescents engaged  in  recreational  sports  and  leisure  time physical  activity  (PA)  self-report  use  of  anabolic steroids and other banned substances. Some studies  show  that  around  6%  of  adolescent  athletes involved  in  organized  sports  in  the  United  States have used AAS at least once in their lifetime. Other studies show that at least 10% of amateur, youth athletes, or leisure time exercisers attending fitness centers engage in illicit PED use. These findings are alarming because they show that the use of illicit PEDs  is  not  a  problem  limited  to  the  elite  sports community. The reported prevalence rates among larger  populations  of  leisure  time  exercisers  and noncompetitive  athletes  indicate  that  illicit  PED use is a growing and emerging public health risk. In fact, it can be argued that the health benefits of exercise  and  PA  can  be  offset  by  the  use  of  illicit PEDs, especially among chronic users and younger people.

Licit Performance-Enhancing Drugs

Nutritional  supplements  and  licit  performance-enhancement substances provide an alternative to illicit  drug  use  in  sports  with  no  to  minimal  side effects  on  users.  These  products  include  a  wide variety  of  substances,  such  as  proteins,  herbal-based products (e.g., Tribulus Terrestris), creatine, amino  acids,  stimulants  (e.g.,  caffeine),  multivitamins,  and  diet  drugs.  There  is  evidence  that most of these substances yield benefits to physical health (e.g., the antioxidant properties of vitamins and  herbal  products  support  immune  functioning), and increase athletic performance in diverse ways.  Given  their  “legal”  nature,  nutritional supplements are widely used in both professional and amateur sports, across age groups, and even among  people  who  engage  in  exercise  for  recreational purposes.

Nevertheless,   there   are   several   reasons   to question  the  apparent  legality  and  safety  of  licit performance-enhancement   substances.   First, nutritional  and  dietary  supplements  are  not  subject  to  strict  testing  and  scrutiny  by  official  regulatory  authorities,  such  as  the  Food  and  Drug Administration   (FDA).   Consequently,   many supplements  may  be  contaminated  with  illegal PEDs, commonly anabolic steroids, or with other toxic substances, such as heavy metals. Such contamination  can  pose  serious  threats  to  consumer health  and  safety.  Second,  official  reports  reveal that  elite  athletes  tend  to  abuse  legal  nutritional supplements  by  concurrently  using  up  to  20  different substances, a practice known as “stacking.” The lack of proper regulation and labeling of the ingredients  and  the  uncontrollable  use  of  dietary supplements  raise  questions  about  the  safety  licit PEDs. Specifically, unknown interactions between substances,  and  liver  toxicity  resulting  from  prolonged  use  or  abuse  of  PEDs,  may  prove  health-threatening. Finally, several studies suggest that the systematic use of licit PEDs may act as a gateway to  the  use  of  illicit  substances,  especially  among junior and early-career athletes. Thus, while legal PEDs can yield benefits to the user, there are major concerns  surrounding  safety  of  use.  Also,  the  use of  licit  PEDs  may  enforce  a  mentality  of  drugassisted  performance  enhancement,  and  this  may increase the risk to use illicit PEDs.

Determinants and Consequences of Performance-Enhancing Drug Use

The  main  reasons  for  PED  use  include  weight management,  improvement  of  physical  stamina, building leaner muscle mass and burning fat, and/ or gaining other health benefits, such as a healthier skin or countering the effects of aging. In this respect, body image disturbances (e.g., body checking, investment in appearance) and social physique anxiety  (SPA)  can  be  related  to  the  use  of  PEDs. Further, nutritional supplement users, particularly adolescents, are willing to engage in excessive use of  supplements  to  achieve  a  better  physique  or improve  performance,  and  tend  to  overlook  the health risks involved in excessive use of nutritional supplements.

Prevention and Education

Drug  control  mainly  applies  to  the  use  of  illicit PEDs  in  sports,  as  the  use  of  legal  performance enhancement  substances  is  still  unregulated  by official  international  sporting  associations.  The ATLAS  (Adolescents  Training  and  Learning  to Avoid Steroids) and ATHENA (Athletes Targeting Healthy Exercise and Nutrition Alternatives) projects  are  based  on  education,  awareness-raising, and  training  of  adolescent  athletes  to  increase abstinence from licit and illicit PEDs.


PEDs  can  be  either  licit  or  illicit,  and  they  are used  mainly  to  increase  athletic  performance  and improve  physical  appearance.  The  use  of  illicit PEDs is related to adverse health problems and is banned from international sporting organizations. Athletes  using  such  substances  face  legal  sanctions and career termination. The potential negative outcomes of illicit PEDs may explain why the use of licit PEDs, typically known as nutritional or dietary  supplements,  has  expanded  considerably in  both  athletes  and  non-athletes.  Licit  PEDs  may bring several health benefits to the user and assist performance  enhancement.  Nevertheless,  careless  and  excessive  use  of  nutritional  supplements and lack of proper regulation of the supplements’ actual  ingredients  pose  threats  to  the  health  of users. Most importantly, using nutritional supplements from an early age may reinforce polypharmacy  trends  and  accordingly  facilitate  transition to illicit PEDs (the gateway hypothesis). Preventive efforts and educational approaches for illicit PED abstinence, as well as the safe use of licit PEDs are needed.  Action  should  be  also  taken  to  regulate the ingredients and labeling of legal PEDs, so as to reduce the risk of contaminated products.


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