Clomiphene is usually used for fertility in females, but the mechanism is the same in males. It works by blocking the estrogen receptor in the hypothalamus, which causes it to release more GnRH, which then stimulates gonadotropin, then LH and FSH, which in turn stimulates the gonads to do their thing.

If you were on TRT and wanted to restore fertility, it's a good way to do it. You probably wouldn't want to be on it permanently since it has some mood side effects due to it's estrogen blocking effects.