On the eve of the most controversial sports event of the 21st century so far, one swimmer is explaining how it felt to take banned drugs for the first time. “I was anxious, to be honest,” says Andriy Govorov, the 50m butterfly world record-holder. “Because there’s no way back.”

The 34-year-old Ukrainian points to his backside. That is where the first needle carrying performance-enhancing drugs went into his body. Then to his stomach. That one hurt less. “I don’t like needles being stuck in me,” Govorov says. “When I was younger, I would pass out when I had blood tests.”

But Govorov is being mightily rewarded for signing up for the Enhanced Games in Las Vegas this Sunday. The event has been called the Steroid Olympics, because it allows athletes to use anabolic steroids, testosterone and human growth hormone, which are outlawed in elite sport. But the rewards are great for those involved. If all goes well, Govorov could end up around $1m richer.

Yet he is far from alone in chasing riches in the desert. There are 42 athletes competing in the Enhanced Games, in swimming, athletics and weightlifting, of whom around half are Olympians. They include Britain’s Ben Proud, who won a 50m freestyle swimming silver medal at the Paris Games, and Fred Kerley, the 2022 world 100m champion and Paris 2024 bronze medallist.

Proud is on a mid-six-figure salary with Enhanced. If he were to win the 50m and 100m freestyle, and swim faster than the current world records, he could walk away with another $2.5m. Not bad money for a swimmer who was struggling to get by on lottery funding when he was training for the Paris Olympics.

Yet the idea of an event that trumpets the use of banned drugs has appalled traditional sports and the bodies that regulate them. The World Anti-Doping Agency, for instance, calls it a dangerous and irresponsible concept. “Over the years, there have been many examples of athletes suffering serious long-term side-effects from their use of prohibited substances and methods,” it says. “Some have died.”

However, the Enhanced Games’s co-founder Christian Angermayer is unrepentant. The 48-year-old German became a billionaire betting early on unconventional industries such as bitcoin, biotech and psychedelic drugs. He is confident that anti-ageing and performance enhancers will be the next big thing.

“I believe we are just at the beginning of a global, decade-long megatrend of human enhancement and consumer biotech,” he says. “Products that slow or reverse ageing, tap into human vanity, and measurably improve health, performance and happiness have a 100% total addressable market.”

Angermayer believes that people will watch the Enhanced Games and then go to its website where a range of prescription drugs, including testosterone cream, peptides and human growth hormone are available for sale.

Wada warns that while these drugs have been approved by the US Food and Drug Administration it does not mean they are safe. It points out that taking testosterone, the most common banned drug, “can lead to an increased risk of hypertension, heart attack, and blood clots, as well as infertility and testicular shrinkage, increased aggression, anxiety and depression”.

Angermayer insists that such drugs, when used under strict medical supervision, are far healthier than substances such as alcohol and cigarettes which society permits.

“I’m a conservative libertarian,” he says. “I am very much for body autonomy. Freedom only makes sense with knowledge. That’s why I want to have this limiting factor of medical supervision. I believe alcohol and sugary drinks should need a prescription. You should have to go to your doctor and he might say, ‘OK, you can have one Coke a week.’”

Other critics have claimed that Enhanced Games is inherently Maga, given early backers included Donald Trump Jr and Peter Thiel. That is something Angermayer denies. “No, we’re not,” he says. “Science is not political. Sport is not political. We are not political.”

Angermayer is not a typical tech-bro billionaire. He is gay. He doesn’t drink alcohol. He also owns the world’s biggest triceratops skull, which he plans to install in his London apartment. But he does share an instinct for knowing where society is heading, for better or worse.

When asked what success for the Enhanced Games looks like, he is blunt. “A few world records broken and hopefully hundreds of millions if not billions of people watching it, not from A to Z, not for four hours, but in a world of social media having eyeballs on our clips.” But ultimately it is about selling products isn’t it? “Yes,” he says.

Meanwhile, as Govorov prepares to race he insists he has carefully balanced the risks and rewards. “It’s not a blind overuse of enhancements,” he says. “You have to undergo a health check, are told about the benefits and the risks, and you decide for yourself if you want to do it or not.”

Govorov, who also holds a master’s degree in political science, says when he broke his world record aged 26, he was fuelled only by creatine, a legal supplement, and espressos. But now, with drugs and the aid of a swimsuit that would also be banned in competition, he believes he can go faster than his old best. If he does, he will make $500,000 for 20 seconds of work, to go with his salary.

Does he worry about the side effects? “I don’t have major ones,” he says. “The only thing is sometimes oily skin and more pimples. And other than that, some anxiety.” He pauses. “And besides that, I now have financial stability. I have 10 times more financial benefit than I used to have.”