I spent a couple of years on breastnexum before starting HRT and creating an account here. I'm also one of those folks who had a blood clot. It turns out that even on a low dose of an oral phytoestrogen, my liver is happy to create excessive amounts of the enzymes that cause clots. The one in my calf could have caused major problems, but it didn't. It was the first thing I told my doc when I prepared to start HRT and it's the reason I remain on patches to this day. Oral estradiol would likely cause the same issue for me.
Thank goodness for informed consent. I live in a state that permits it, so I'm allowed to decide if I "need" HRT and I have a doctor who supervises my medication. Win-win.
But the herbal stuff was working for me. After being flat as a board for my entire life, I was getting development. Still, I don't recommend it. And I believe that many, if not most people on breastnexum want to transition but convince themselves they're just "men who want to grow breasts." That was the case for me.