The World Anti-Doping Agency (WADA) on Thursday said a 21-month investigation into suspicions of widespread doping in Kenya had found no evidence of "institutionalised" drug-taking.
"The doping practices of Kenyan athletes are unsophisticated, opportunistic, and uncoordinated and there is no evidence of an institutionalised system," WADA said in a report launched in Nairobi.
The probe was begun in December 2016 by WADA's Intelligence and Investigations Department in collaboration with the Anti-Doping Agency of Kenya (ADAK) and the Athletics Integrity Unit (AIU).
The so-called 'Kenya Project' found that the banned substances most commonly used are the steroid nandrolone and blood booster EPO.
The report added that athletes were either "insufficiently educated" or "wilfully blind" when it came to doping.
"Kenya is a great and justly proud athletics nation, but it now has a serious doping problem," said AIU chief Brett Clothier.
A total of 138 Kenyan athletes have failed drugs tests since 2004 with the vast majority caught during in-competition testing.
Among these are female marathon champions Rita Jeptoo and Jemima Sumgong, and three-time men's 1,500m world champion Asbel Kiprop, who is under provisional suspension.
A WADA-approved blood testing laboratory was recently established in Kenya, the first in the region.
Gunter Younger, WADA's director of intelligence and investigations, said: "We take the doping practices in Kenya very seriously and have been working hard to identify their extent and nature in Kenyan athletics as well as trying to work out the best possible response."
"What we have determined is that doping in Kenya is not sophisticated or organised and does not appear to be institutionalised," he added.
Last week WADA lifted a ban on Russia's anti-doping agency, paving the way for Russian athletes to return to competition across all sports, despite revelations in 2015 of a vast Russian-backed scheme to avoid drug testers.
Nothing like that was found in Kenya, despite the prevalence of doping in the East African country which has become popular with distance runners from around the world seeking high altitude training.
WADA said that having identified the nature and scale of the problem it was now necessary for Kenya government bodies and world agencies to work together to end the practice of doping.
"This is an important day for clean sport in Kenya and it is great to see the level of cooperation that already exists," said Humphrey Kayange, chair of Kenya's National Olympic Committee (NOC).
"We need to ramp up the education of athletes and their entourages so that ignorance and wilful neglect of responsibilities are reduced," he said.