What's the Deal with Prohormones?

I dont really understand pro hormones for one main reason, you shouldn’t do an oral only cycle because your natty test will be crashed and you aren’t replacing it with test injections, so surely that happens EVERY pro hormone cycle?
But then some people rave about pro hormones… Anyone know much about them? Are they effective? Are they worth using?

Cheers guys

Deh roids much better. There just isnt enough info with PH imo, we really dont know how harsh they are on the body.

If they work I assume they crash the natty test levels and if they dont then they might not crash the levels.

Stay away from them IMO.