A man who played a role in a £40m international steroid smuggling ring arranged dozens of unlicensed shipments of the drug from India into Europe, a court heard.
Following a six-week trial at London's Old Bailey, the 65-year-old was found guilty of conspiring to import a class C drug.
Dhillon arranged dozens of unlicensed shipments of the drug from India into Europe, the court head.
He will be sentenced next month alongside Mumbai-based Jacob Sporon-Fielder, 38, and Nathan Selcon, 44, from Maidenhead in Berkshire, both of whom had earlier pleaded guilty to their roles in the group.
Part of a five-year investigation, seizures of anabolic steroids by the National Crime Agency (NCA) have totalled in excess of £40m.
Officers believe the operation, headed by Sporon-Fielder, the chief executive of an Indian-based pharmaceutical firm, has been responsible for 42 tonnes of the drug being smuggled into the UK.
The probe was launched in 2014 when around 300 kilos of the class C regulated drug – bound for an address in Belfast – were seized by Border Force officers at Heathrow Airport.
Made by Sporon-Fiedler’s pharmaceutical company in India, the illegally imported drugs were shipped using Dhillon’s contacts.
Once in the UK, they would be distributed by Selcon to be sold to bodybuilders and fitness fanatics on the black market.
Rob Burgess, NCA regional head of investigations, said: “We believe this organised criminal group to be the most prolific of its kind ever uncovered, probably the biggest global players in the illicit anabolic steroid market.
“They had the ability to move tonnes of anabolic steroids into Europe, where they would be sold on the black market, pocketing millions of pounds in profit. These drugs were completely unregulated and not subject to the usual stringent checks, therefore they posed potentially major health risks to those who used them.”
Mr Burgess added: “This investigation has identified importations totalling almost 42 tonnes of illegal steroids, however it is likely they were responsible for far more.”
Nick Jariwalla, head of Border Force at Heathrow, said: “Border Force works hard to keep individuals and communities safe from the illegal importation of illicit drugs like these. By making seizures, Border Force not only disrupts the supply chains but, as was the case here, can also provide the crucial first evidence that helps bring those responsible to justice.”
Dhillon, Sporon-Fiedler and Selcon will be sentenced next month.