It's like the Olympics - except steroids are allowed

American sprinter Shania Collins says the fact that those taking part in the games admit to doping, already gives them more integrity than cheaters.

"We're being up front and honest and transparent from the start," she tells the BBC. "So how can you challenge our integrity when we're forthright with the information?"

Some sporting governing bodies have publicly rebuked athletes for choosing to compete in the games.

UK Athletics' chief executive Jack Buckner said he was "appalled" when it was revealed former Great Britain sprinter Reece Prescod had signed up in January. UK Anti-Doping (Ukad) has called the event a "reckless venture".

Meanwhile, GB Aquatics has said British swimmer Ben Proud will not be selected again for Britain's Olympic team if he competes at the Enhanced Games.

Proud, who won the silver medal in the 50m freestyle at the Paris Olympics in 2024, is hoping to break the world record using performance-enhancing drugs and win a million dollars on Sunday.

If he wins the race but doesn't break the world record, he will still make $250,000 (£185,000).

"There's no money in sport," Proud told the BBC before the games. "I was 30 and had just come off a silver medal, what future path do I follow?"

Proud, who has been widely condemned for joining the Enhanced Games, has said it would take 13 years of winning World Championship titles to earn this kind of prize money.

Enhanced has already paid a doped up swimmer a million dollars for breaking a record, during one of the trials it hosted ahead of Sunday's competition.

Of the 42 athletes competing at the Enhanced Games on Sunday, most will be using testosterone and some will also be using human growth hormone and stimulants like Adderall.

But not everyone will be doping - some are competing clean.

American swimmer Hunter Armstrong has said he "definitely" doesn't want to dope for the games, adding: "I personally have taken pride in getting as far as I can on natural God-given talent."

He plans to compete clean for a shot at the money and then return to compete at the Los Angeles Olympics in 2028. Whether he can is unclear, given the outcry from many sports bodies responsible for selection.

However, the US Anti-Doping Agency's Tygart told the BBC as long as an athlete passes doping tests to qualify for the Olympics, there's nothing to stop them from taking part.

Earlier this month, the Enhanced Group - the company behind the competition - began trading on the New York Stock Exchange.

And the competition is seemingly being treated as an opportunity for Enhanced to sell performance-enhancing medicine and supplements at the event and online.

This sparks broader concerns for some, at a time when social media is awash with offers to buy unregulated peptides and pressure on people to look a certain way.

Joe Vennare, founder of Fitt Insider, which analyses the health and wellness industry, feels normalising performance-enhancing drugs will bring unknown health and cultural consequences.

He says people have the right to use legal medical interventions, but is concerned some people are doing so at the expense of being fit and having a healthy diet.

"Kids are using social media filters, they're getting Botox injections," he tells the BBC. "They're having body dysmorphia - especially young men, in this case at record numbers."

Vennare says the Enhanced Games reflects those problems, but hasn't created them.

"That's a problem that parents and culture and society more broadly have to address."

Enhanced athlete James Magnussen agrees. The Australian swimmer says parents need to control what their kids watch and take personal responsibility - but he insists Enhanced is not "targeted at children".

"It's an entertainment company and product targeted at people looking at the longevity and human performance space."

None of these criticisms of the Enhanced Games are likely to go away any time soon.

Neither the athletes taking part, nor the invite-only crowd in Vegas, seem to be deterred.