Progesterone

In a social setting I was talking to a doc about TRT and he claimed that men on TRT should have their progesterone levels checked and that treatment with progesterone was warranted. For him it was one of the main replacement hormones that he used with men. While I'm pretty much up to date on treatment with T, HCG and an AI as indicated, I have no knowledge of the role of progesterone in a replacement setting. In women, yes. With men, no. Any info out there?

Progesterone