RecruitingPhase 2Drug trialGrowth Hormone Replacement in Veterans With GWI and AGHD (GWIT)The goal of the GWIT Study is to assess whether growth hormone replacement therapy is a safe and effective treatment for veterans with Gulf War Illness (GWI) and adult growth hormone deficiency (AGHD). The main questions the study aims to answer are: 1. Is growth hormone effective at reducing fat in the trunk of the body and symptoms of GWI among veterans with GWI and growth hormone deficiency? 2. Do the results of the study suggest there is merit in pursuing a larger trial to examine the efficacy of growth hormone as a treatment for growth hormone deficiency among veterans with Gulf War Illness? To determine eligibility for the study, veterans will be asked to complete several assessments including questionnaires, blood tests, and a scan of the brain. Participants who qualify for the study will receive recombinant human growth hormone for 6-months. A body composition scan will be performed at Day1, Day 90, and Day 180 of the intervention. Questionnaires and cognitive tests will also be collected before and after the trial.