Nonalcoholic fatty liver disease (NAFLD), fatty infiltration of the liver in the absence of alcohol use, is an increasingly recognized complication of obesity, with prevalence estimates of about 30% of individuals in the United States. A subset of these will develop progressive disease in the form of nonalcoholic steatohepatitis (NASH), which can progress to cirrhosis and liver failure. The investigators hypothesize that LUM-201 (Ibutamoren mesylate) will decrease intrahepatic lipid accumulation as quantified by proton magnetic resonance spectroscopy (1H-MRS).

Inclusion Criteria:

1. Age 21-60yo and generally healthy
2. BMI ≥ 25 kg/m2
3. Radiographic or histologic diagnosis of NAFLD / NASH
4. Insulin-like growth factor-1 (IGF-1) level <3rd quartile of normal for age

Exclusion Criteria:

1. Contraindications to MRI imaging
2. Diabetes mellitus or use of diabetes medications
3. History of cancer, significant renal disease, decompensated or unstable cardiovascular disease
4. Cirrhosis or known liver disease other than NAFLD
5. Pregnancy or breastfeeding
6. Known pituitary or hypothalamic disease affecting the growth hormone axis
7. Chronic use of drugs causing hepatic steatosis in the past 12 months (chronic oral steroids, methotrexate, tamoxifen)
8. Treatment with medications that may interact with LUM-201 (ibutamoren mesylate)

Adverse events were followed for each patient starting at the time of the screening period (minimum 0.5 months, maximum 3 months), during the six-month treatment phase (6 months), and for one month after the subject's last study visit. This represents a total time frame for adverse event assessment of approximately 7.5 months to 10 months.

Adverse events are defined as any untoward or unfavorable medical occurrence in a participant, including any abnormal sign (for example, abnormal physical exam or laboratory finding), symptom, or disease, temporally associated with drug exposure, whether or not considered related to drug exposure. Adverse events were assessed through regular investigator assessment at all study visits and at other points of patient contact between visits.