Slash took heroin because it "complemented" his personality.
The Velvet Revolver rocker has revealed he was drawn to the Class A drug when he was in Guns N' Roses because it suited him "perfectly" and helped him escape reality.
He said: "Heroin was like the ultimate complement to my personality. It just fitted perfectly. Everyone else was doing coke and speed, and made hyper people even more hyper. Whereas heroin just made me more reclusive and quieter. It was just me and my drug.
"It was escapism for me."
However, the legendary musician admits his addiction eventually became out of control.
When asked how much he used to do, he told GQ magazine: "However much I could get my hands on. If I finished a batch, I'd go hunting for it. It never stopped.
"I always injected. It's the only way as far as I'm concerned, go straight to the source."
These days, the 44-year-old rocker - who has two sons with his wife Perla Ferrar - is currently clean of drugs and has also given up alcohol.
Despite his eventful past, Slash admits he has no regrets.
He explained: "I don't miss it at the moment. Three years ago, I got really stressed because Velvet Revolver were in a state, and my marriage was in a state, and I went back down that road for a while, and while it was fun for a minute, it wasn't nearly as much fun as it had been before. I'd just grown out of that lifestyle.
"I don't regret any of it. I don't believe in having regrets. I haven't killed anyone, or anything like that. But I did go into rehab after that, for a month, and I really haven't wanted drugs since then.
"I dropped everything. And I feel good."