Inclusion Criteria:  OEF/OIF/OND Veteran Score of 1 or more on Combat Experiences sub-scale of Deployment Risk and Resilience Inventory-2 (DRRI-2) One or more TBI on Military-specific sub-domains of Boston Assessment of Traumatic Brain Injury-Lifetime (BAT-L) GH deficiency diagnosed by: macimorelin stimulation test (cut point 5.1 mcg/L) Score of 11 or more on QoL-AGHDA 4-week stability on any psychotropic medications 3-month stability on all other hormone treatments Able and willing to provide informed consent to participate in this study, and complete study protocol  Exclusion Criteria:  History of moderate or severe TBI History of neurologic disorder other than TBI with substantial impact on quality of life History of bi-polar disorder, schizophrenia, or other concurrent psychotic disorder Active suicidal ideation (no plan required) as determined by a score of 2 points or more on the Columbia Suicide Severity Scale (C-SSRS) suicidal ideation rating, or overt suicidal behavior in the past 6 months Contraindication to rhGH therapy Contraindication to macimorelin use Acute medical illness, active infection, cancer or decompensated chronic medical illness Evidence of substance abuse disorder in the past 6 months other than mild alcohol or cannabis use disorder; nicotine use is allowed Urine toxicology evidence of the use of an illicit drug, excluding cannabis, within the past 90 days prior to screening Scoring less than 41 on Trial I of the Test of Memory and Malingering (TOMM) BMI >35 or body weight >350 lbs  Pituitary anatomy documented by an MRI using a sella protocol within the past 2 years indicating abnormalities consistent with an etiology other than mild-TBI  i.e., pituitary mass Women who are pregnant or of child-bearing potential not on contraception Current use of the following: growth hormone, estrogen or estrogen-like dietary supplements, progestin, IGH-I, or chronic glucocorticoid use in supraphysiologic doses Currently enrolled in any other interventional study unless prior approval is provided by the study chairs and the study sponsor (Cooperative Studies Program)