Sam Bramman's harrowing journey of addiction and recovery started at a house party aged just 19.
It was there he first tried nitrous oxide, a gas substance colloquially know as "nangs", which were freely available from tobacconists and other retailers.
''I was told the high would only last a few seconds," the 22-year-old told AAP.
''I'd seen ... ads on Facebook for services delivering them.
''I didn't think it could take me where it did.''
Before long, he was inhaling as many as 50 eight-gram canisters of the drug, also called laughing gas, every day.
Mr Bramman tried to hide his addiction from his family as it took stronger hold of him.
But then it sent him into a state of psychosis.
"I travelled from Sydney to the Gold Coast, completely out of touch with reality," he said.
''I thought the police and people were after me.''
His parents flew from their home in Kellyville, in north-west Sydney, to take him to hospital.
He had to be medically sedated before spending the next two months on a psychiatric ward.
A new-found love of running kick-started his recovery.
It eventually prompted him to run from Sydney to Canberra, raising awareness of the harms of nangs and campaigning government for stricter regulations.
"Running's my new addiction," he said.
As well as serious mental health and neurological impacts, nitrous oxide misuse has been linked to severe vitamin B12 deficiency, severe frostbite, lung injuries, cardiac abnormalities, asphyxiation, and injuries associated with falls.
With the help of Mr Bramman's work with the NSW government, regulations come into effect from Thursday.
The gas - legitimately used in industries like medicine and hospitality - can no longer be sold to people under 18.
There are limits on the amount of nitrous oxide that can be sold to consumers, the hours it can be sold between and how it can be displayed in shops.
The health department has launched a public awareness campaign on the harms of misuse, and distributed guidance to retailers and suppliers.
Health Minister Ryan Park said he believed they struck a good balance between preventing harm from the substance and keeping it available for legitimate use.
''This is an important change that will hopefully see fewer young people fall victim to the harms of nitrous oxide misuse,'' he said.
Businesses and individuals who fail to comply with the new rules could be liable for fines, as well as being issued warnings or having products seized.
Mr Bramman has welcomed the changes but wants more work to be done, including a push for the Therapeutic Goods Administration to implement nationwide scheduling changes to the substance.
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