It supposedly helps what I'd call "modulate" Estrogen (along with Indole 3 Carbinol - big debate on what's better - I'd just eat Broccoli): It supposedly alters the *type* of Estrogens produced, not the overall level.
If it's a health thing, where you are in range and just want to try to improve what's produced within range - worth a shot. But if you *REALLY* need an AI (aka - "my nipples are on fire and it hurts to cross my arms in front of me") - they won't do Jack.