The 52-year-old music mogul caries a can of the gas and believes taking regular breaths helps him look younger and stay relaxed.
A source told The Sun newspaper: "Simon knows he`s not getting any younger and is trying every trick to tackle it.
"He says it helps him relax and keep the stress at bay."
The `X Factor` chief recently discussed his use of health-boosting vitamin injections and even administered the treatment to an unnamed famous female friend.
He said: "These vitamins, you can feel them going through your entire body and I mean your entire body.
"I did say to this girl, you are going to have a slightly unusual experience here.
"Then five minutes before we were going to go on air she was in one of the dressing rooms and she actually had two orgasms during it. True story. You should try it."
Earlier this year, it was revealed Simon had sought therapy to help him quit smoking after 44 years.
A source said: "Simon made it his New Year resolution. He`s been smoking since a very young age and feels the time is now right to try and stop.
"He has no major health issues at the moment but, as always, he is under a lot of pressure with his work schedule.
"Simon`s mother and some of his closest friends have been nagging him for some time about trying to stop smoking. His grandfather Robert was a heavy smoker who died of lung cancer. His father suffered a heart attack. It`s made Simon think long and hard about his own health now."