The singer said drugs had made him “cocky” and “arrogant” before he kicked his habit.
He told Danny Baker on Radio 5: “I’ve been helping Eminem over the last 18 months and he’s doing brilliantly.
“I’m there if people want my help. If people ask for help you tell them where to go but there’s no point advising people if they don’t want to do it.”
He said he knew George Michael had criticised him in the past but said it was “none of my business”.
He also said he felt sorry for singers “catapulted to fame” on reality television who struggled to cope when their careers declined.
He said: “Suddenly they become very famous, like Joe (McElderry) who just won X Factor, who is a sweetheart but he’s got to go and play live and he’s had no experience of doing that.”
The full interview of Sir Elton will be broadcast on Radio 5 live from 1000 on January 2.