I believe it’s a Designer steroid (not really prohormone) that they missed in the wave of bans because they used the wrong scientific name when banning it. It was in a supplement called Mass Destruction by Blunt Nutrition that got a lot of flack for being ‘dangerous’.
“18-methylestr-4-en-3-one-17b-ol is a relatively unknown in the prohormone world. Mostly because of the few products that contain it, none are popular, or come from trusted brands. Another brand includes it in a blend in a product called Androgeddon by Anabolic Androgenic Research (AAR). It’s alpha isomer is actually a controlled substance, and it’s believed that the act that banned the alpha isomer was actually intended for 18-methylestr-4-en-3-one-17b-ol. Nonetheless all we really know about 18-methylestr-4-en-3-one-17b-ol is that it is “deca” like in effects. I personally do not know anyone who has used it, which also means we know little about how hepatotoxic it really is”
In other words, take another steroid and stay away! My opinion