Yeah they’re really lacking, but we do know that estrogen blocks testosterone production. In fact, a lot of people just take a high dose of estrogen and no antiandrogen and the estrogen is enough to suppress their testosterone levels. It’s called estradiol monotherapy
Absolutely! You have to take a lot though, more than you’d take otherwise and typically more than you can take with oral I think so most people who do it do injections, but it definitely does work