Metformin and Muscle Recovery

Inclusion Criteria:

1. Age between 60y and older
2. BMI: \<30 kg/m2
3. Good general medical health, ambulatory and in independent living setting
4. Adequate upper body strength to use assistive walking device (crutches, walker, etc) as assessed by PI/staff during screening
5. Clinical Frailty Scale score \< 3
6. Mini-Cog score \> 3

Exclusion Criteria:

1. History of cardiovascular disease (e.g., CHF, CAD, MI, CVA)
2. History of endocrine or metabolic disease such as hypo/hyperthyroidism and diabetes (Treated hypo/hyperthyroid for at least 6 months will be permitted)
3. History of kidney disease or failure (CKD \> stage 4; serum creatinine \>1.5mg/dL)
4. History of vascular disease
5. Risk of DVT including family history of thrombophilia, DVT, pulmonary emboli, myeloproliferative diseases including polycythemia (Hb\>18 g/dL) or thrombocytosis (platelets\>400x103/mL), and connective tissue diseases (positive lupus anticoagulant), hyperhomocystinemia, deficiencies of factor V Leiden, proteins S and C, and antithrombine III
6. Use of anticoagulant therapy (e.g., Coumadin, heparin)
7. Uncontrolled hypertension - Elevated systolic pressure \>150 or a diastolic blood pressure \> 100
8. Implanted electronic devices (e.g., pacemakers, electronic infusion pumps, stimulators)
9. Cancer or history of successfully treated cancer (less than 1 year) other than basal cell carcinoma
10. Chronic systemic corticosteroid use (≥ 2 weeks) within 4 weeks of enrollment and for study duration (intra-articular/topical/inhaled therapeutic or physiologic doses of corticosteroids will be permitted)
11. Androgens or growth hormone within 6 months of enrollment and for study duration (topical physiologic androgen replacement will be permitted)
12. Inability to abstain from smoking or vaping for duration of study
13. Currently taking estrogen products (topical estrogen products will be permitted)
14. Currently on weight loss diet or medication
15. History of stroke with motor disability
16. A recent history (\<12 months) of GI bleed
17. History of liver disease or AST/ALT 2 times above the normal limit
18. History of respiratory disease (acute upper respiratory infection, history of chronic lung disease)
19. Any staff members who report directly to the principal investigators