The man behind one of social media’s most widely circulated addiction and recovery blogs has a backstory that resonates with many of his followers. Kevin Alter spent the better part of 12 years of his life homeless and in and out of addiction, which is a truth that he does not hide while running “The Addict’s Diary.”

“I lost my entire 20s to a syringe and a bag of heroin,” Alter, who is now three years sober, told Fox News.

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Alter, now 31, first became addicted to drugs during his high school years on Long Island when he and his friends got their hands on cocaine. At just 17, Alter said, “he couldn’t stop from the first time I ever tried it.”

It didn’t take long for his parents to catch on, and he was sent to the first of 29 inpatient treatment centers. When he got out, he completed his senior year and graduated, but then rejoined his old circle of friends.

“All my friends were doing drugs, and I got back into it and began the game of hiding it from my family the best I could,” he said of his first relapse. “You get better with that as you grow in your addiction.”

He said that while he was introduced to the 12-step program and narcotics anonymous meetings, as a teen he “never really totally grasped onto it.”

“I wasn’t willing to let go of people that I needed to, that’s a difficult thing to do when you’re a kid,” he said.

He managed to get a scholarship to college, but after his first year, he came back home to the same group and was introduced to a new drug: heroin. He said he spent three days sniffing the drug before someone pushed a syringe his way on the fourth.

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“I’m not your typical heroin addict that got a prescription and started abusing pills,” he said. “I started pretty much straight with heroin, and so from there — heroin would take over my life for the next 11 years.”

Those 11 years were full of rehabs, homelessness, family heartbreak and many deaths of friends.

"It sucked," he said.

There were times he would sober up long enough to get a job and collect a paycheck while managing to keep the fact that he was living in a Queens train station a secret. It wasn’t until he found himself living in the stairwell of a building in the Bronx with a friend that he met in detox that he realized he wanted to get off the streets.

“Every bridge had been burned, but someone presented me with an opportunity to go to treatment and they offered to come [and] get me,” he said. “I didn’t even want to get clean — you have to put yourself in the frame of mind of going in and out of treatment for 12 years, coming from this good family of law enforcement and firefighters, and you’re just this lost person out there, I really didn’t think I could get clean. I just assumed I was going to be a heroin addict forever.”

“I lost my entire 20s to a syringe and a bag of heroin." — Kevin Alter

But in his 29th treatment facility, Alter was asked to write his life story and was shocked when someone close to his age could only write down five bullet points.

The next day, Alter read 46 pages of his life story to his group. His therapist took him aside told him that he failed to list the actual reasons he got high, and he responded that he had never thought about it before.

“She said, ‘You get high because you hate yourself,’” he recalled.

Alter said her words triggered his feelings from when he first started using. It was low self-esteem and other insecurities that pushed him toward the drugs, and he realized he had to learn how to love himself while sober.

So for three years, Alter, who has gained nearly 570,000 followers in the 22 months since creating “The Addict’s Diary,” which was born almost overnight after he wrote a poem about a friend who died, has learned how to love himself, and considers himself “the luckiest heroin addict alive.” He doesn’t shy away from hiding his truths with his followers either, while also helping them share their own stories and recovery journeys. Many of his posts go on to be shared thousands, if not millions, of times.

He credits his parents, who kicked him out at 18 and had money set aside for his funeral, with helping him move forward.

“Once they saw that I was different, it took about a year, but they didn’t bring up the past anymore,” he said. “They were just so happy that I was OK.”

"I just assumed I was going to be a heroin addict forever.” — Kevin Alter

Today, Alter said he is working on a podcast and spends his time traveling to different high schools and speaking to students, while also running “The Addict’s Diary” and answering calls from both addicts and people trying to help someone struggling.

“The most common call I get is a mom [who] wants their kid to get help and has the means and can afford to get help but can’t get the kid to accept help, and they’re just getting run over by their kids,” he said.

Alter said the page's popularity has helped him when reaching out to people in need. He also said it aids in keeping lines of communication open. With the holidays coming up, Alter said it’s likely that the calls will increase and emphasized the importance of finding sober support.

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“This is the highest relapse period for anybody and everybody,” he said. “Whether its people who are alone or people that haven’t been reconnected with family, they’ll fall off. Or for people who have reconnected, it’s a stressful time. It’s a reminder of how far behind they are and it’s just a stressful time of year for people.”

Alter, having missed plenty of holidays and celebrations over the years with his own family, said spending the time he has now making amends with himself and with his relatives has helped him cope with lost time.

"It's been a beautiful process," he said.