An enkephalin is a pentapeptide involved in regulating nociception (pain sensation) in the body.

[2] There are three well-characterized families of opioid peptides produced by the body: enkephalins, β-endorphin, and dynorphins.

[3] The proopiomelanocortin gene (POMC) also contains the met-enkephalin sequence on the N-terminus of beta-endorphin, but the endorphin peptide is not processed into enkephalin.

[citation needed] Enkephalin is also considered a neuropeptide, which in the human body performs as an important signaling molecule in the brain.

[4] A 2017 study indicates that this polypeptide may be linked to brain functioning during the stress response, especially in the hippocampus and prefrontal cortex.