AUCKLAND, NEW ZEALAND - JUNE 19: NRL great Andrew Johns looks on prior to the round 15 NRL match between the New Zealand Warriors and the Sydney Roosters at Mt Smart Stadium on June 19, 2016 in Auckland, New Zealand. (Photo by Anthony Au-Yeung/Getty Images)

Winning it all – Premierships, State of Origin series and three Dally M Medals is sure to leave a lasting legacy on the game.

But unfortunately, playing the game at the highest level for so long has left an unwanted legacy on the man himself – eighth Immortal Andrew Johns. The rugby league legend has been in chronic pain since bringing his 249 first-grade game career to a close 15 years ago.

“Playing professional rugby league for 15 years resulted in my body suffering a lot of trauma, including a broken back in 2003,” Johns lamented in a release from Levin Health.

“Then I had to get a neck fusion which forced me to retire in 2007.”

Despite his jocular nature on TV and incredible feats on the field, Johns has been unable to exercise regularly or engage in some of his favourite past-times like surfing – which led to him seeking treatment from less conventional methods.

Johns has since found relief in an unlikely place – medical marijuana.

The success of his treatment and a desire to shake off the stigma surrounding the alternative therapy have resulted in Johns joining the Sports Advisory Board at Levin Health, alongside premiership AFL coaches Damien Hardwick and Alastair Clarkson, as well as WNBA and Opals superstar Lauren Jackson.

“I've had ongoing chronic pain following injuries that occurred during my playing years and using medical cannabis has helped ease a lot of the symptoms,” Johns said.

"Since taking medicinal cannabis for the last 18 months I can get back in the water and exercise with hardly any discomfort – neither of which I could do in recent years.

“The big positive is I haven't taken an anti-inflammatory tablet during that time.”

According to data from the Therapeutic Goods Administration (TGA), over 60% of Australians are now turning to medical cannabis for pain relief. The establishment of the Sports Advisory Board Johns is joining is an attempt by Levin Health to raise awareness and education about its use in treatments for sporting injuries.

“I really want to de-stigmatise the notion that is still prevalent around medicinal cannabis, and Levin is doing just that,” said Johns.

“I'm thrilled to be joining the Sports Advisory Board alongside a credible list of other sporting names in a bid to help educate.”

Meanwhile, Levin Sports has received ethics approval for a world-leading clinical trial to investigate the effectiveness of medicinal cannabis in treating people with chronic pain following musculoskeletal injury. The study will be conducted in conjunction with LaTrobe University's Sport and Exercise Medicine Research Centre.