Bodybuilding superstar Rich Piana had 20 bottles of steroids in his home at the time of his medical emergency ... this according to the police report obtained by TMZ Sports.

Cops were called to Piana's Florida home at 1:30 PM on Monday after the 46-year-old social media sensation suddenly collapsed in his bathroom while getting a haircut from his girlfriend, Chanel.

Piana's girlfriend says she tried to catch the former Mr. California bodybuilding champ when he collapsed but couldn't due to his massive size and weight. Chanel told officials Piana struck his head during the fall.

The 911 operator instructed Chanel to perform CPR but she was unable to revive him.

When emergency personnel arrived, paramedics found crushed up white powder on a table along with a credit card and straw and decided to give Rich 2 doses of Narcan (often used to treat opiate overdoses) to try and revive him.

Chanel told responders Rich had battled opiate addiction in the past but she believed he was clean.

Rich never regained consciousness and was transported to a nearby hospital where he was placed into a medically induced coma.

The report notes that police found bottles and bottles of testosterone in the home, 20 in total. Chanel said Rich is an admitted steroid user who's been juicing for more than 20 years.

Chanel also noted Rich had suffered from a slightly enlarged heart at one point in his life -- but didn't know if that contributed to the medical emergency.