This is a double-masked placebo controlled study of glyceryl trioleate-glyceryl trierucate (Lorenzo's Oil (LO)) therapy in adrenomyeloneuropathy (AMN), the adult form of X-linked adrenoleukodystrophy (X-ALD). AMN is a slowly progressive distal axonopathy that involves the long tracts of the spinal cord and differs from the rapidly progressive inflammatory cerebral forms that most commonly affect boys and adolescents. All forms of X-ALD are associated with the abnormal accumulation of very long chain fatty acids (VLCFA) in plasma and tissues. The oral administration of LO normalizes plasma VLCFA levels within 4 weeks. While previous therapeutic trials of LO therapy in patients with the cerebral forms of X-ALD have been disappointing, recent studies suggest that it is beneficial in two types of X-ALD: 1) as a preventive of neurological involvement in asymptomatic boys; and 2) in AMN, where it appears to slow the rate of progression. None of the previous studies have been controlled, and we are now conducting the first placebo-controlled trial.