“I don’t like to express views on numbers, but I think what you find is that when the substance has been new on the list, there is a time for people to sort it out,” Mr. Howman said. “Methylhexaneamine was a similar situation. There were a number of cases in the first three or four months.”

A Standard Process

Though the banning of meldonium has quickly generated results, WADA did not accelerate the process that put it on the agency’s list.

“It was done in a very scientific way with all the information from papers and so forth received and considered,” Mr. Howman said. “It followed the normal process.”

That process, according to Mr. Howman, began in earnest in early 2014. It apparently got a push when Usada received a tip in March 2014 from a person whose identity has remained confidential, claiming that athletes from Eastern Europe were using meldonium to enhance their performance. The existence of that tip, reported first by USA Today, was confirmed on Saturday by an American antidoping official who requested anonymity.

The tip led to further research on meldonium, also known as Mildronate, by Usada. Eventually, it led to a research project funded in part by the Partnership for Clean Competition, an organization founded in 2008 by the United States Olympic Committee, Major League Baseball, the N.F.L. and Usada to support antidoping research.

On Sept. 29, 2014, shortly before Dr. Bowers’s presentation in Arizona, meldonium was added to WADA’s 2015 monitoring program, putting it on a list of substances earmarked for extra scrutiny that were being considered for inclusion on the banned list. Michael Pearlmutter, the executive director of the Partnership for Clean Competition, said Dr. Bowers and Mario Thevis then met in Vienna in November 2014.

Dr. Thevis is a German biochemist who works at a laboratory in Cologne and is one of 13 experts who make up WADA’s prohibited-list group, an influential international panel that largely determines which substances are considered for the monitoring list and then for prohibition.