There are some competitions with testing. However, seeing the physiques of the competitors on the relevant websites, I'm convinced they do indeed use anabolics or at least something to cut fat:
I guess the testing may be somehow fraudulent, or maybe it's just a fundamentally misconcieved procedure: maybe it's not possible to test for use of all or certain substances.
There are tested orgs but most, if not all are not considered pro. They do lie detector tests. I don't know if any do actual blood tests. Steroids, especially test, are hard to check for.
https://naturalbodybuilding.com
https://www.worldnaturalbb.com
I guess the testing may be somehow fraudulent, or maybe it's just a fundamentally misconcieved procedure: maybe it's not possible to test for use of all or certain substances.