Craig Carlin, of Cross Green, Leeds, also quit smoking and drinking before undergoing a massive lifestyle change to become a degree student and a bodybuilder.
The 39-year-old part time Tesco worker said people looked down on him when he was a "skinny" drug addict, but now he gets compliments on this physique and says he wants to be the world's biggest natural bodybuilder.
Mr Carlin said he was aged around 15 when his life spiralled out of control after his father Steven, who was aged in his early 40s, died by suicide.
Mr Carlin suffered from depression and started using drugs and was addicted to heroin for ten years
Mr Carlin said: "Years later I heard my mum Christine also died by suicide aged in her mid fifties.
"I regretted not being there for her and my drug use spiralled out of control. I smoked heavily and drank daily.
"I wandered from homeless services to occasionally sleeping on the streets."
Mr Carlin said he started to change his life six years ago after meeting his partner Fatima.
He said: "At first I was still drinking, smoking and collecting a methadone prescription and antidepressants from the chemist. I was constantly angry and depressed
"I don't know how she coped with me, or why? Till this day I wonder what she saw in me. Over the period of a few months seeing the way people looked at me, probably saying things
like 'tramp' began to get to me.
"One day I said 'that's it, I'm through with people looking down at me.' In that moment I decided to not collect my prescription, and never went back for another.
" I felt the need to channel all that raw aggression at the world, I took up natural bodybuilding, and took it to the extreme.
" I kept my mind busy by enrolling on a mathematics degree with the Open University.
"Then I got a job working for Tesco three nights a week, while committing hours a day to my degree and bodybuilding.
"My bodybuilding has since got to the level of a pro. My ambition is to to be the biggest natual bodybuilder in the world and at the same time establish my own supplements line."
"It's hard to imagine that only a few years before I was a skinny, submissive drug addict, that never wanted to live to see the next year.
"Now my outlook on life is that, no human being is better than another. The only thing that separates us, is our will and drive."