In humans there are two members of this family called mir-33a and mir-33b, which are located in intronic regions within two protein-coding genes for Sterol regulatory element-binding proteins (SREBP-2 and SREBP-1) respectively.

[2] miR-33 plays a role in lipid metabolism; it downregulates a number of ABC transporters, including ABCA1 and ABCG1, which in turn regulate cholesterol and HDL generation.

[3][4] Further related roles of miR-33 have been proposed in fatty acid degradation and in macrophage response to low-density lipoprotein.

[2] It has been suggested that miR-33a and miR-33b regulates genes Involved in fatty acid metabolism and insulin signalling.

[7] miR-33, along with miR-122, could be used to diagnose or treat conditions related to metabolic disorders and cardiovascular disease.