PhytoSERM to Prevent Menopause Associated Decline in Brain Metabolism and Cognition

Inclusion Criteria: 1. Peri- or postmenopausal women with the latter defined as last menstrual period (LMP) completed ≥ 60 days and ≤ 4 years, per the Stages of Reproductive Aging Workshop (STRAW) criteria. 2. Age 45-60 years. 3. Presence of hot flashes ≥ 7 per day. 4. In good general health as evidenced by medical history. 5. Clinical laboratory values must be within normal limits or, if abnormal, must be judged to be not clinically significant by the investigator. 6. No medical contraindications to study participation. 7. Stable medications for 4 weeks prior to the baseline visits. 8. Provision of signed and dated informed consent form. 9. Stated willingness to comply with all study procedures and availability for the duration of the study. 10. Ability to take oral medication and be willing to adhere to the PhytoSERM regimen. 11. For females of reproductive potential: Negative pregnancy test and use of highly effective contraception by male partner for at least 1 month prior to screening and agreement to use such a method during study participation. 12. Fluent in English or Spanish. Exclusion Criteria: 1. Known allergies to isoflavones or soy-based products. 2. Evidence of cognitive impairment on the Mini-Mental State Examination (total score \< 27). 3. Pregnancy 4. Use of estrogen or progestin compounds within 8 weeks of baseline. 5. Use of investigational agent within 12 weeks of baseline. 6. Concurrent neurologic, systemic, or psychiatric disease that would influence cognition or ability to provide informed consent and to participate. 7. Known or suspected estrogen-dependent neoplasia, active neoplastic disease, history of breast cancer, or at risk of developing breast cancer, endometrial hyperplasia. 8. History of epilepsy, focal brain lesion, head injury with loss of consciousness or Diagnostic and Statistical Manual of Mental Disorders (DSM IV) criteria for any major psychiatric disorder including psychosis, major depression, bipolar disorder, alcohol or substance abuse. 9. Thrombophlebitis, thrombosis, thromboembolic disorders, myocardial infarction, ischemic heart disease, cerebrovascular accident, stroke, transient ischemic attack (TIA). 10. Current use of tobacco or a history of alcohol abuse. 11. Use of drugs, herbs, or dietary supplements to treat menopausal or cognitive symptoms less than 8 weeks prior to baseline. 12. Evidence of any significant clinical disorder or laboratory finding. 13. Known allergy to soy-derived products/ proteins or branded over the counter products; hypersensitivity to estrogens or progestins. 14. Visual and auditory acuity inadequate for neuropsychological testing 15. Inability to undergo MRI scans 16. Inability to undergo PET scans