Sphingosine (d18:1), an amino alcohol, is chiefly recognized for its 18-carbon unsaturated hydrocarbon chain. Nevertheless, in mammalian tissues, both sphingosine and its variant, dihydrosphingosine, feature hydrocarbon chains ranging from 12 to 26 carbons. Sphingosine (d15:1) represents a naturally rare variant, serving as an internal standard for chromatographic or spectrometric analyses of sphingoid compounds.