Inclusion Criteria:  Provide a personally signed and dated informed consent document indicating that the subject has been informed of all pertinent aspects of the study and is willing and able to participate. Have diagnosis of X-linked adrenoleukodystrophy (X-ALD) by genetic testing and elevated VLCFAs. Present clinical features of AMN, or adrenal insufficiency. Subjects must be 18 years of age and older.  Exclusion Criteria:  Have the cerebral form of X-ALD, based on medical records, or based on MRI performed within the last 12 months or MRI at screening Have been treated with any drug targeting TRβ or with any drug being tested as therapy for X-ALD AMN form within the past 30 days before screening History or presence of clinically significant acute or unstable hepatic, renal, gastrointestinal, pulmonary, immunological, endocrine, diabetes, hematological or oncological that in the opinion of the investigator would pose a significant risk for the subject Subject has untreated primary adrenal insufficiency based on morning plasma cortisol and ACTH at screening Lorenzo's Oil. Currently taking Lorenzo's Oil or erucic acid containing product, or other lipid lowering agent known to effect VLCFA levels