The Physiology Behind Performance-Enhancing Drugs (Basic)

Thomas Hicks

In 668 BC, Charmis won the Olympic 200-yard running race after eating a preparation of dried figs (Yesalis and Bahrke 2002). In 1904, Thomas Hicks ate strychnine, brandy and five eggs to increase his endurance and help him win the Olympic marathon (Jones 2012). Since the beginning of organized competitive sports, professional athletes have experimented with ways to increase their athletic potential.

Today, this process is termed doping, or using performance-enhancing substances to increase athletic ability. The World Anti-Doping Agency (WADA) was created to level the playing field between athletes and assist sport organizers in combatting the problem of doping (World Anti-Doping Agency 2012b). Every year, WADA publishes a list of prohibited substances; testosterone and other anabolic-androgenic steroids (AAS) are at the top of the list (World Anti-Doping Agency 2012b). In 2010, testosterone and AAS were found in 60% of the blood and urine samples that tested positive for containing an illegal substance (World Anti-Doping Agency 2010).

Testosterone is an androgen, a hormone that is normally found in the body.  It controls the development of sexual organs and secondary sex characteristics that occur in puberty.  It is also involved in muscle development. Testosterone, by binding to the androgen receptor, controls expression of the genes responsible for these changes (Deroo and Korach 2006). With doping, athletes take advantage of this natural process and try to find ways to increase the levels of testosterone in their body to enhance their muscle development (Storer et al. 2003).

However, changing the natural balance of testosterone also leads to the development of several medical conditions.  Men using high doses of AAS can have estrogen levels as high as women during a normal menstrual cycle, leading to breast development (Wilson 1988). Women develop facial hair but lose scalp hair.  Both sexes develop higher levels of cholesterol in their blood, leading to blockage of the arteries and heart attacks (Shahidi 2001). In athletes from the former East Germany, these effects have even been transferred on to the athletes’ children who suffer from asthma, allergies and crippled feet or legs (World Anti-Doping Agency 2012a).

While some athletes think abusing testosterone is worth the risk, doping is like playing a game of Russian roulette. Eventually, an athlete is going to lose. Although much is known about hormonal regulation, androgen receptors are expressed in many different types of cells, so many of the long term effects of testosterone abuse are unknown. Also, athletes caught doping can be disqualified, banned from future competitions, or stripped of their medals (International Olympic Committee 2012). What’s the point of being an athlete if you can’t compete?

Learn more technical details about performance-enhancing drugs.

By: Kirstin Roundy, University of Utah
Kirstin Roundy holds a M.S. in Laboratory Medicine and Biomedical Science from the University of Utah. She spent 14 years working as a biomedical researcher studying the gene regulation in B cell development. She enjoys acquiring knowledge and takes random, non-credit classes just so she can learn something new. Her favorite sport is soccer.


Bowers, L. D. 2009. The international antidoping system and why it works. Clin Chem. 55:1456–61.

Deroo, B. J. and K. S. Korach. 2006. Estrogen receptors and human disease. J Clin Invest. 116:561-70.

International Olympic Committee. 2012. Anti-Doping Rules. Retrieved from

Jones, D. S. 2012. Olympic Medicine. N Engl J Med. 367:289-92

Shahidi, N. T. 2001. A review of the chemistry, biological action, and clinical applications of anabolic-androgenic steroids. Clin Ther.  23:1355-90.

Storer, T. W., L. Magliano, L. Woodhouse, M. L. Lee, C. Dzekov, J. Dzekov, R. Casaburi, S. Bhasin. 2003. Testosterone dose-dependently increases maximal voluntary strength and leg power, but does not affect fatigability or specific tension. J Clin Endocrinol Metab. 88:1478–85.

Wilson, J. D. 1988. Androgen abuse by athletes. Endocr. Rev. 9:181–99.

World Anti-Doping Agency. 2010. Adverse Analytical Findings and Atypical Findings, Reported by Accredited Laboratories. Retrieved from

World Anti-Doping Agency. 2012a. Sport Physicians Tool Kit. Retrieved from

World Anti-Doping Agency. 2012b. The 2012 Prohibited List. Retrieved from

Yesalis, C. E. and M. S. Bahrke. 2002. History of doping in sport. Pages 1-20 Performance-enhancing substances in sport and exercise, 1st edn, Human Kinetics, Champaign, IL, USA.

Articles by Kirstin Roundy.

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