The only real anti-progesterone is RU-486 which is too new to really no the agonistic, OR antagonisitc effects it can have on the male body
Prolactin inhibitors are Bromocriptine, Cabergoline, Pergolide
You can also run 200mg of B6 to keep prolactin down during a cycle
If your asking because of Deca or Tren concerns. Neither convert to progesterone. Run a test and you won't have to worry about progesterone.
"The tragedy of life is not found in failure but complacency. Not in you doing too much, but doing too little. Not in you living above your means, but below your capacity. Never failure but low aim, is life's greatest tragedy"- Benjamin Mayes
"The power of accurate observation is commonly called cynicism by those who have not got it"- George Bernard Shaw