Australian swimmer James Magnussen has taken drugs and says he has never felt better as he embraces being the pioneer of performance enhancements in sport.

The dual Olympian, the first athlete to sign for Enhanced Games, claims other Australians will inevitably join him at the multi-sports event without drug testing.

Magnussen will be a centrepiece of Enhanced Games’ launch in Las Vegas on Wednesday (Thursday AEST).

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Australian-born entrepreneur Aron D’Souza, said to have financial backing from multi-billionaires, will detail dates and venue for next year’s inaugural games.

Magnussen is the poster boy for an event featuring swimming, track and field and weightlifting, which financiers say will be a shop-front for an anti-ageing industry potentially worth trillions of dollars.

Last year he said he would “juice to the gills” if the pay day for a world record was $1 million, with organisers responding by setting the bonus at $1.5m.

This week Magnussen said he recently took his first course of performance enhancements over eight to 10 weeks in the United States.

“Having to inject yourself with a performance enhancing substance is quite a confronting thing,” Magnussen told AAP in an interview in Las Vegas on Tuesday.

“A lot of it’s just the stigma attached to it that has been built up over years that probably started way back in the ‘80s, and I’d been brought up with.

“That (injecting) was the most confronting thing about the whole process.

“But then it just becomes part of your routine. You get your doctor’s check-ups, you go through the process and you realise it’s no drama.

“If there had have been negative side effects on my health or my fertility or anything like that, then I would question my involvement.

“But now I’ve done it, I’m the first athlete to openly and honestly do it, and I know the data, I’m very comfortable with it.

“Not only will my data help me for my preparation, hopefully it’s pioneering for the other athletes that come on board.”

There were “pros and cons” for the 34-year-old freestyler who won an Olympic silver and two bronze medals before retiring after the 2018 Commonwealth Games.

Magnussen said his general health improved; his swimming didn’t.

Medicos told Magnussen he “might put on a bit of muscle” in four to six weeks after starting enhancements.

“Within 10 days, I put on 10 pounds (4.5 kilograms) of muscle,” he said.

“I just was getting bigger and stronger and my strength just went through the roof.

“Halfway through my protocol, I probably could have gone to a 50m swimming race or Mr Olympia.

“I was just getting so big and so strong and we didn’t know that would happen.

“In terms of health metrics, my resting heart rate lowered, my blood pressure lowered, my cholesterol lowered - my fitness was really good.

“They were the things that I think everyone was worried about and they were actually not an issue at all.”

Magnussen and Enhanced Games will detail his specific enhancement program — drugs, doses, timings, feedback. But not yet.

“Enhanced, first, will come out and talk about that and document it and from there I can then follow on and be really open and honest with substances, dosages, effects, what I do differently next time,” Magnussen said.

“It’s a whole new world. For me, it broke down the stigma.

“Personally, I always had this perception of performance-enhancing drugs should never be used in sport and they’re dangerous. It’s what you learn in the textbook at school, right?

“But actually there hasn’t really been open and honest dialogue about these things — how they’re used, what the effects are — and I think they’ve been demonised in a lot of ways.

“Do I think they belong in tested sport? No.

“But do I think they’re safe to use in this environment? Absolutely.”

Magnussen planned to get as fit as possible before taking performance enhancements in months leading to the inaugural games.

“The enhancements I see as like the cherry on top,” he said.

“That will be the last eight to 12-week part ... you have done the hard work, you’re in the shape you need to be — that’s the cherry on top of that.”

This AAP article was made possible by support from the Enhanced Games.