Atenolol for the Prevention of Osteoporosis (APO)

Inclusion Criteria: * Able and willing to provide informed consent * Postmenopausal women (FSH ≥ 16 IU/L) (no menses for at least one year) * Aged 50-75 years Exclusion Criteria: * Clinical diagnosis of diabetes mellitus requiring insulin * Clinically significant abnormality in any of the additional screening laboratory studies * A1c- ≥8 * Calcium - \> upper limit lab value per site * AST- 2x upper normal limit * FSH- \< 16IU/L * eGFR- \< 45 mL/min/1.73m2 based on creatinine * CBC- Per PI interpretation of each patient * Presence of (documented clinical diagnosis of any of the following): * Significant liver or renal disease * Malignancy (current diagnosis including myeloma or melanoma) * Radiation (the site PI will determine eligibility on a case-by-case basis) * Malabsorption (current clinical diagnosis or actively receiving treatment) * Hypoparathyroidism (current clinical diagnosis or actively receiving treatment) * Hyperparathyroidism (current clinical diagnosis or actively receiving treatment) * Acromegaly * Cushing syndrome * Hypopituitarism * Severe chronic obstructive pulmonary disease * Pheochromocytoma (current clinical diagnosis or actively receiving treatment) * History of cardiac failure * Ejection Fraction \<35% (based on most recent EF within the last 12 months, if available) * PR interval \> 200 msec on screening ECG or known heart block * History of bronchospastic disease with treatment (asthma, bronchitis) * Gastric Bypass * Parkinson's * Rheumatoid Arthritis * Psoriatic Arthritis * Connective Tissue disease * Undergoing treatment with any medications that affect bone turnover, including the following: * adrenocorticosteroids (oral for \> 3 months within the past year or year-round use of inhaled corticosteroid use) * anticonvulsant therapy for seizures (carbamazepine, phenobarbital, or phenytoin within the previous year) pharmacological doses of: thyroid hormone (causing decline of thyroid stimulating hormone below normal, i.e. \< 0.3 miU/L) bisphosphonates (within the past 3 yrs; if taken orally \>1 month in past 3 years) denosumab, romosozumab, estrogen therapy (does not include creams or suppositories) or treatment with a selective estrogen receptor modulator, or teriparatide/abaloparatide (\> 1 month within the past year); aromatase inhibitors (\>1 month within the past year) * Current use of digitalis glycosides * Thiazides (\< 6 months of use prior to screening) * Current or within the past 3 months use of beta blockers * Any recent fracture within the past 6 months prior to screening (other than fingers, toes and facial fractures, which are all acceptable) * Bilateral hip replacements or metal in both hips * Patients with serum 25-hydroxyvitamin D levels of \< 20 ng/ml, in order to ensure vitamin D sufficiency * Resting systolic blood pressure \< 115 mm Hg, heart rate \< 55 bpm (average of 3 readings after a 5-minute rest and one minute between readings with an automatic cuff)