Choline Dose Ranging in Postmenopausal Women

Inclusion Criteria: * Women aged 50-65 years * Postmenopausal: Women who are postmenopausal will have not had a period in the last 12 months, have FSH\>30 IU/L, and estradiol (E2) \<50 pg/ml. * Nonsmokers * Not taking hormone therapy, SSRIs, phytoestrogens, SERMS, or antiestrogen medications and will be at least one year without such treatment * Physically healthy * No cardiovascular disease other than mild hypertension. Subjects will also not have current untreated or unremitted Axis I or II psychiatric or cognitive disorders (see screening below). * IQ in the normal range \>80 * Normal neuropsychological test performance Exclusion Criteria: * MCI or dementia - Montreal Cognitive Assessment \<26, Mattis Dementia Rating Scale \<130, and Global Deterioration Scale \>2 * History of cancer treatment with cytotoxic and/or ongoing (current) maintenance targeted chemotherapy * Blood pressure \> 160/100 (untreated) * Untreated thyroid disease * Significant cardiovascular disease * Asthma or COPD * Active peptic ulcer * Hyperthyroidism * Epilepsy * Current untreated or unremitted Axis I psychiatric disorders Use of medications on the Prohibited medications (see list)