Sphingosine (2-amino-4-trans-octadecene-1,3-diol) is an 18-carbon amino alcohol with an unsaturated hydrocarbon chain, which forms a primary part of sphingolipids, a class of cell membrane lipids that include sphingomyelin, an important phospholipid.

Sphingolipid metabolites, such as ceramides, sphingosine and sphingosine-1-phosphate, are lipid signaling molecules involved in diverse cellular processes.

Sphingosine is synthesized from palmitoyl CoA and serine in a condensation required to yield dihydrosphingosine.

Dehydrosphingosine is then reduced by NADPH to dihydrosphingosine (sphinganine), acylated to dihydroceramide and finally oxidized by FAD to ceramide.

Sphingosine is then solely formed via degradation of sphingolipid in the lysosome.