Editor’s Note: This page has been retired and is no longer being updated.

CNN  — 

Here’s a look at the use of performance-enhancing drugs in sports.

Facts

“Doping” by professional athletes has been acknowledged as a problem since at least the 1960s.

The issue gained prominence as a result of the Bay Area Laboratory Co-Operative (BALCO) investigation, tell-alls by former professional athletes, a 2007 report on drugs in professional baseball and a scandal involving Russia’s 2014 Olympic team.

About Performance-Enhancing Drugs

There are several types of performance-enhancing drugs, including anabolic steroids, stimulants, human growth hormone and diuretics.

Anabolic steroids are natural and synthetic substances which help build muscle mass, enabling athletes to train harder and recover quickly from strenuous workouts.

Tetrahydrogestrinone, also known as THG or the Clear, is a powerful steroid purportedly used by such high profile athletes as track star Marion Jones and baseball player Barry Bonds.

Stimulants, including amphetamines, impact the central nervous system, increasing alertness and decreasing appetite.

Human growth hormone (HGH) is taken for improved endurance and strength.

Androstenedione is a supplement that was sold over-the-counter until the FDA took action in 2004. It is banned by the NFL, Olympics, NCAA and MLB. The supplement is an anabolic steroid precursor, meaning that the body converts it into testosterone.

Diuretics are banned because they can be abused to mask other drugs in urine tests, and they are also taken to achieve rapid weight loss.

Timeline

1967 - The International Olympic Committee (IOC) establishes a Medical Commission in response to an increase in the usage of performance enhancing substances.

1981 - After American discus thrower Ben Plucknett tests positive for steroids, he is banned from participating in future events by the International Amateur Athletics Federation (IAAF) and he is stripped of his world record.

1987 - The National Football League (NFL) begins testing players for steroids.

1988 - The US Congress passes the Anti-Drug Abuse Act, which makes possession and distribution of anabolic steroids for non-medical purposes a crime.

1990 - Congress strengthens the 1988 law by classifying anabolic steroids as a controlled substance.

1999 - The World Anti-Doping Agency (WADA) is established.

2000 - The US Anti-Doping Agency (USADA) is established.

2002 - Federal authorities launch an investigation into BALCO, a California lab that is suspected of selling performance enhancing drugs to athletes.

2003 - Major League Baseball (MLB) begins testing players for steroids.

February 2005 - “Juiced: Wild Times, Rampant ‘Roids, Smash Hits and How Baseball Got Big,” an autobiography by retired baseball star Jose Canseco, is published. In the book, Canseco recounts his own steroid use and implicates other players.

March 2005 - Six former and current Major League Baseball players testify before the House Government Reform Committee about drugs in baseball. They include Mark McGwire, Sammy Sosa and Canseco.

March 2006 - MLB Commissioner Bud Selig announces an investigation into steroid use among pro baseball players. Former US Sen. George Mitchell will lead the investigation.

August 22, 2006 - The USADA bans sprinter Justin Gatlin for eight years after he tests positive for banned substances a second time. Gatlin is also forced to forfeit his 100-meter world record.

May 2007 - 1996 Tour de France winner Bjarne Riis admits using performance-enhancing drugs to win his title. Race organizers tell him to return his yellow first-place jersey.

September 20, 2007 - Cyclist Floyd Landis is stripped of his 2006 Tour de France title and is banned for two years after a positive test for synthetic testosterone.

December 13, 2007 - The Mitchell Report is released. MLB players named in the steroid report include Bonds, Roger Clemens and Andy Pettitte.

February 2008 - Former New York Mets clubhouse employee Kirk Radomski is sentenced to five years probation after pleading guilty to distributing steroids.

February 2009 - Alex Rodriguez admits to using performance-enhancing drugs while playing for the Texas Rangers.

January 2010 - McGwire admits to using steroids during his career.

February 2012 - Three-time Tour de France winner Alberto Contador is stripped of his 2010 title for doping.

June 2012 - The USADA confirms that it is opening proceedings against Lance Armstrong and five former teammates. Armstrong denies the charges. (For more details about Armstrong’s case, see Lance Armstrong Fast Facts).

August 2012 - American cyclist Tyler Hamilton is stripped of his gold medal from the 2004 Olympics after he admits to doping.

January 2013 - MLB announces it will begin random testing for HGH.

July 2013 - Ryan Braun of the Milwaukee Brewers is suspended without pay for the rest of the 2013 season for violating the league’s drug policy.

August 2014 - Anthony Bosch, the founder of a Miami anti-aging clinic, surrenders to the Drug Enforcement Administration. He later pleads guilty to a charge of distributing steroids to athletes. His sentence is four years in federal prison.

September 2014 - The NFL and NFL Players Association reach an agreement regarding the league’s performance-enhancing drug policy. The agreement calls for HGH testing and an overhaul of the drug program.

January 2015 - Kenya’s Rita Jeptoo, a three-time Boston Marathon champion, is banned from competition for two years for doping.

September 2015 - The DEA announces that 90 people have been arrested and 16 underground steroid labs have been shut down in a sweeping drug bust called Operation Cyber Juice.

November 9, 2015 - A WADA report details evidence of doping in Russian athletics and a “deeply rooted culture of cheating at all levels.” Russia is later provisionally suspended as a member of the International Association of Athletics Federations.

March 2016 - At a press conference, tennis player Maria Sharapova admits to failing a drug test at the Australian Open. She is initially suspended for two years, but the ban is later reduced to 15 months.

July 18, 2016 - A WADA report alleges Russia ran a state-sponsored doping program during the 2014 Sochi Winter Olympics. On December 9, 2016, WADA releases an update to the report concluding that a”systematic and centralized cover-up” benefited more than 1,000 Russian athletes across 30 sports.

August 4, 2016 - The IOC announces that 271 athletes from the 389-member Russian Olympic team have been cleared to participate in the 2016 Rio Olympics. The rest of the team - 118 athletes - are banned in the wake of the doping scandal.

August 7, 2016 - A swimmer from the Chinese Olympic team tests positive for a banned substance called hydrochlorothiazide, a blood pressure drug that doubles as a diuretic.

August 11, 2016 - John Anzrah, a sprint coach for the Kenyan Olympic team, is sent home after allegedly posing as an athlete to take a drug test. He is the second Kenyan running coach to face allegations that he tried to help athletes cheat on doping tests. Michael Rotich, the team’s track and field manager, reportedly tried to bribe undercover journalists posing as coaches, offering to pay them in exchange for advance warning about drug tests.

August 24, 2016 - The International Weightlifting Federation reports that 15 Olympic weightlifters, including three Chinese gold medalists, have tested positive for illegal growth hormones and other banned substances in doping retests.

January 25, 2017 - The IOC rules that Usain Bolt’s 2008 gold medal in the 4x100m relay no longer counts after one of his teammates tests positive for methylhexaneamine, a banned substance.

June 29, 2017 - Michelle Payne, a Melbourne Cup-winning jockey, is banned from competing for four weeks after failing a drug test.

December 5, 2017 - The IOC announces that Russia is banned from the 2018 Winter Olympics in South Korea because of the country’s “systematic manipulation” of anti-doping rules. However, Russian athletes who can prove that they are clean will be “invited” to compete. The ban is the most wide ranging punishment ever meted out by the IOS on a participating country. Russia’s Olympic Committee is also ordered to reimburse the IOC $15 million for the cost of the investigation and to help establish a new Independent Testing Authority.

February 1, 2018 - The Court of Arbitration for Sport (CAS) overturns lifetime bans on 28 Russian athletes accused of doping, making them eligible to compete in the 2018 Winter Olympics. In 11 additional cases, the athletes are suspended from participating in the 2018 Winter Olympics but they are cleared to compete in future events as the court rules that lifetime bans were not justified.

February 9-25, 2018 - The IOC allows 169 Russian athletes to participate in the 2018 Winter Olympics. They are not members of a Russian team. Instead, each participant is called an “Olympic athlete from Russia.” They do not carry the Russian flag or wear uniforms that identify them as Russian. Their medals are not added to to country’s Olympic medal count.

February 28, 2018 - The IOC announces that it is lifting the suspension on Russia participating in the Olympics. The country’s status is restored after investigators confirm that there were no additional doping violations by Russian athletes who competed in the 2018 Winter Olympics.

December 9, 2019 - WADA unanimously agrees to ban Russia from major international sporting competitions – notably the Olympics and the World Cup – for four years over doping non-compliance. On December 17, 2020, CAS reduces the ban to two years.

March 9, 2020 - Federal prosecutors announce more than two dozen people involved in the horse racing industry have been indicted for taking part in a scheme to give racehorses performance-enhancing drugs to help them win races around the world. One of the defendants is trainer Jason Servis, who prosecutors say “doped virtually all horses under his control,” including Maximum Security, the colt that crossed the finish line first in the 2019 Kentucky Derby but was disqualified for interference.

March 12, 2021 - The UK’s Medical Practitioners Tribunal Service (MPTS) finds that former British Cycling and Team Sky doctor Richard Freeman is guilty of ordering testosterone “knowing or believing it was to be administered to an athlete to improve their athletic performance.” Following the MPTS decision, UK Anti-Doping (UKAD) has placed Dr. Freeman on “a provisional suspension from all sport.”

May 1, 2021 - Medina Spirit wins the 147th running of the Kentucky Derby. Just over a week later, Hall of Fame trainer Bob Baffert reveals the 3-year-old colt tested positive for elevated levels of betamethasone, an anti-inflammatory corticosteroid sometimes used to relieve joint pain in horses, throwing Medina Spirit’s victory into question.

February 8, 2022 - It is announced that 15-year-old Kamila Valieva, a member of the ROC figure skating team, tested positive for a banned substance. Valieva is provisionally suspended but on February 14, the Court of Arbitration for Sports rules she is able to compete in the women’s single skating short program event and the women’s single skating free skating event at the Beijing Olympics.