A prohormone is NOT the equivalent of a designer AAS which both diendione and methylstenbolone are.
The primary distinction is a "prohormone" exhibits little to no intrinsic activity absent certain metabolic processes that convert it into the active compound.
As far as effectiveness is concerned, I'm awaiting that evidence on behalf of supplement manufactures, but don't hold your breath.
One thing is for certain, some of the most hepatotoxic AAS are those currently listed as designer AAS, and were once being sold as "prohormone" supplements.
Are pro hormones safe? If they are effective and elicit an anabolic response similar to AAS their RISK will be NO LESS.
There's two issues with pro-hormones that make them an unattractive AAS substitute IMO.
Unlike many of the AAS that are in use today and are available by RX, or have a relatively prolonged, (albeit much of it anecdotal) track record, there is NO credible scientific evidence that has evaluated their safety AND efficacy as anabolic agents.
WHAT HAS BEEN REPORTED? Several of these agents have been removed from the market bc of "toxic" (usually hepatic) adverse effects.
BUYER BEWARE!