This product is a high purity omega-hydroxy very long chain fatty acid methyl ester that is ideal as a standard and for biological studies. Omega-oxidation is a minor fatty acid pathway used for fatty acid metabolism and usually occurs in the smooth endoplasmic reticulum. Eicosanoic acid is enzymaticaly converted to the 20-hydroxyeicosanoic acid as well as to the eicosadicarboxylic acid as part of the omega-oxidation metabolic pathway. Stimulation of omega-hydroxylation has been proposed as a method for treating X-linked adrenoleukodystrophy, a disease that is characterized by elevated levels of very long chain fatty acids.1 Omega-hydroxy fatty acids have an important role acylated to various lipids. Omega-hydroxylated very long chain fatty acid (VLCFA) ceramides are vital to skin barrier functions and a deficiency of these lipids can cause death from water loss through the skin. A mutation in an elongase enzyme for VLCFA results in a deficiency in omegahydroxylated VLCFA-ceramides which causes a muscular dystrophy disease, defective skin-water permeability barrier function, and neurological disorders showing the importance of these VLCFA ceramides.2 Sphingolipids (such as sphingomyelin, ceramides, and glucosylceramides) acylated with polyunsaturated and alpha- or omega-hydroxylated VLCFA have been found in the spermatozoa/testes and in the epidermis. Sphingolipids with VLCFA may be responsible for the maturation of these cell.3