The actor publicly denounced the article earlier this week, claiming that it falsely represented his late brother Dan Gordon-Levitt.
But according to the Toronto Sun, the magazine's editors have defended their article and stood by its claims.
"The magazine stands by its reporting, the facts of which are fully supported – and have been confirmed in detail - by the Los Angeles County coroner's office," GQ said in a statement.
Writer Amy Wallace claimed in her article that Dan died of a drug overdose, which Gordon-Levitt described as "factually incorrect" and "irresponsible".
The coroner's office has reportedly confirmed that his cause of death was ketamine intoxication, occurring by intake of overdose, and that the death was officially ruled accidental.
Watch Gordon-Levitt in the trailer for his next film Looper below: