The important thing to remember is that these plant estrogens only stimulate the receptors a fraction of the amount that the hormone estrogen would.  Therefore soy isoflavones can be used to treat conditions of high estrogen activity, by blocking the activity of the hormone estrogen.  They can also treat conditions of low estrogen activity by binding to vacant receptor sites and causing a bit of hormonal stimulation. Soy isoflavones are used to treat menopausal symptoms, like hot flashes, anxiety and depression, and PMS. 

Estrogen is an important hormone for stopping bone resorption by osteoclast cells; therefore the phytoestrogenic isoflavones prevent bone loss (osteoporosis).   Isoflavones also lower LDL (harmful) cholesterol and trigycerides and increase HDL (beneficial) cholesterol thereby decreasing your risk of heart disease.  Finally, unrelated to the estrogenic properties of soy, soy extracts have anti-tumour activity because they regulate enzymes that control cell replication.  Soy extract may be recommended for hormonal imbalances, PMS, menopausal symptoms, osteoporosis, high cholesterol and cancer prevention and treatment.

Isoflavones are found in many plants.  Supplemental isoflavones are usually purified from soy or red clover.  They can be purchased in capsules.  Be sure to purchase a product that has been standardized to the isoflavone content (usually genistein) and guarantee an amount of isoflavones per dose.  This is an assurance that the product contains isoflavones and has some active properties.  Isoflavones can be found in formulas for hormonal balancing and osteoporosis prevention.  Ipriflavone is a synthetic isoflavone that can be purchased separately.

Soy extract should not be used concurrently with estrogen medications.  Women with a history of estrogen sensitive tumours should use soy extract with caution.