Hayley McNeff’s cause of death has been revealed.

The fitness influencer died from “acute intoxication due to the combined effects of heroin, fentanyl, 4-ANPP, cocaine and norbuprenorphine,” Director of Communications for Massachusetts’s Executive Office of Public Safety and Security, Brenna Galvin, told People in a statement on Monday, November 10.

Galvin ruled McNeff’s death an accident, per the report.

Us Weekly has reached out for comment.

News broke in August that McNeff, a bodybuilder, died at the age of 37.

Fitness Star Hayley McNeff’s Death at Age 37 Was ‘Unexpected’

“Such a bright light has left this world too soon with the unexpected but peaceful passing of Hayley C. McNeff on August 8, 2025,” an obituary published by Boston.com read days later.

The obituary continued: “A

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