1. Subjects with cardiac abnormalities considered exclusionary by the study physicians

2. Subjects with uncontrolled metabolic disease, including liver or renal disease

3. Subjects with cancer or recently (6 months) treated cancer other than basal cell carcinoma

4. Any subject currently on a weight-loss diet or a body mass index \>34 kg/m2

5. Recent anabolic or corticosteroids use (within 3 months)

6. Dementia

7. Inability to tolerate an upright position

8. Postural reflexes prohibiting ambulation and inability to follow 2-step commands

9. Any other condition or event considered exclusionary by the PIs and covering physician

Amino Acid Supplementation in Recovery From Traumatic Brain Injury