This product is a high purity alpha-hydroxydihydroceramide and is ideal as a standard and for biological studies. Dihydroceramide is a critical intermediate in the synthesis of many complex sphingoid bases. Inhibition of dihydroceramide synthesis by some fungal toxins that have a similar structure causes an increase in sphinganine and sphinganine-1-phosphate and a decrease in other sphingolipids leading to a number of diseases including oesophageal cancer. Dihydroceramide, synthesized by the acylation of sphinganine, is subsequently converted into ceramide via a desaturase enzyme or into phytosphingosine via the C4-hydrozylase enzyme.1 The presence of a hydroxyl group on the fatty acyl chain of dihydroceramides significantly affects the function and properties of the molecule. While 2(S)-hydroxydihydroceramides can be converted to non-hydroxydihydroceramides in vivo 2(R)-hydroxydihydroceramides cannot. Data presented suggests that 2(R)-hydroxydihydroceramides may interact with some distinct cellular regulatory targets in a specific and more effective manner than their nonhydroxylated analogs.2 2-hydroxydihydroceramides have been shown to be incorporated into the galactosylceramides and sulfatides of the myelin where they are essential to neuronal functions.3