Soy isoflavones are a supplement in pill form you can buy at Walmart, or online, etc. It's a plant-based source of the natural hormone, estrogen. It mimics the drug Clomid, which is prescribed by doctors, to help stimulate your ovaries to ovulate.
So, for instance, some girls use Clomid to help them ovulate, they get it from a doctor, it's a chemical, etc.
Soy isoflavones are pills you buy from the drugstore or online, which is supposed to help do the same thing, without having to go to a doctor, etc.