Grigory Rodchenkov has claimed doping is rife in more than 20 countries as the Kremlin again dismissed the whistleblower's accusation that Vladimir Putin wants to end his life as "pure lies".
Rodchenkov, former head of the Moscow Laboratory, made the claim during his first televised interview since he fled the country after blowing the whistle on the country's doping scheme.
Speaking on CBS' 60 Minutes show, Rodchenkov repeated his insistence that the Russian President wanted to "silence him".
The whistleblower has consistently said he fears for his life after fleeing Russia to seek asylum in the United States.
Rodchenkov was disguised for the televised interview to protect his identity.
"There is information that my life is in jeopardy and we took all necessary steps," he said.
When asked how many Olympic nations were doping, Rodchenkov said "20 plus" and insisted he was sure when pressed further.
He also documented the "simple and effective" sample-swapping scheme found to be present at the 2014 Winter Olympic Games in Sochi.
Rodchenkov's revelations sparked the World Anti-Doping Agency-commissioned McLaren Report, the results of which eventually led to the International Olympic Committee (IOC) forcing Russia to compete at the Winter Olympics here.
He provided testimony to the IOC Commission which was tasked with investigating the evidence presented in the report by the Canadian lawyer.
Although he has commented publicly on the IOC's decision to sanction Russia for their "systematic manipulation" of the anti-doping system at Sochi 2014 through his lawyer Jim Walden, the interview marks the first time he has been heard on camera since the highly-acclaimed Icarus documentary was released last August.
In response to the interview, broadcast on the American network, Kremlin spokesman Dmitry Peskov said it portrayed a man "with emotional if not mental problems".
"Any accusations against our country concerning this matter are absolutely groundless," Peskov added.
"Moreover, what he said about President Putin is nothing but a pure lie."