Law enforcement authorities said they had smashed the biggest illegal steroid ring in US history following a two-year investigation that spanned 10 countries, including China.
"Operation Raw Deal," cracked down on every aspect of the underground network from manufacturing to distribution to the actual buyers, the US Drug Enforcement Agency (DEA) said in a statement.
During the operation, which began in December 2005, some 56 steroid labs were closed, 11.4 million steroid dosage units were seized, as well as 242 kilograms of raw steroid powder "of Chinese origin," the DEA said.
Some 50 people were arrested inside the United States during the operation's final takedown, which began on September 14, the DEA added.
The US operation took place in conjunction with enforcement operations in Mexico, Canada, China, Belgium, Australia, Germany, Denmark, Sweden, and Thailand, it said.
DEA agents "successfully attacked the illegal steroid industry ... from the manufacturers in China who supply the raw materials, to the traffickers in the United States who market the deadly doses," said DEA Administrator Karen Tandy.
Athletes commonly use steroids to increase muscle mass.
Buyers "are solely motivated by a desire to gain an unfair competitive advantage by using illegal performance-enhancing substances," said Terry Vermillion, who heads the Office of Criminal Investigations in the US Food and Drug Administration.
The DEA described Operation Raw Deal as a "four-prong strategy" that focused on raw material manufacturers and suppliers in the China and other countries; US, Canadian and Mexican underground laboratories; US-based websites that sell kits needed to convert the raw steroid powder into finished product; and Internet bodybuilding discussion boards.
The internet chat rooms "are the catalysts for individuals to learn how to illicitly use, locate and discreetly purchase performance enhancement drugs, including anabolic steroids", the DEA stated.
News of the raid follows a series of sports doping scandals in the United States. Baseball's Barry Bonds of the San Francisco Giants has been the subject of persistent accusations of steroid use in recent years.