Met-Enkephalin
Also known as: MENK, methionine enkephalin, OGF
Met-enkephalin is a five amino acid opioid peptide with the sequence YGGFM, derived from the human proenkephalin precursor identified in UniProt under accession P01210. It is one of the body's own opioid signals and is studied particularly in the contexts of pain perception and stress responses. Its molecular mass is approximately 573.67 daltons.
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Overview
Chemical compound
Met-enkephalin, also known as metenkefalin (INN), sometimes referred to as opioid growth factor (OGF), is a naturally occurring, endogenous opioid peptide that has opioid effects of a relatively short duration. It is one of the two forms of enkephalin, the other being leu-enkephalin. The enkephalins are considered to be the primary endogenous ligands of the δ-opioid receptor, due to their high potency and selectivity for the site over the other endogenous opioids.
Mechanism of Action
Met-enkephalin functions similarly to opiate drugs by interacting with opioid receptors, affecting pain perception and stress related pain relief. A longer relative, met-enkephalin-Arg-Phe, is a strong ligand for the mu opioid receptor OPRM1. Met-enkephalin also influences non-opioid systems: through the MRGPRX1 receptor on sensory neurons it can provoke itch without histamine, while the same receptor in the central nervous system is linked to moderating chronic pain signaling.
Research History
Named for its terminal methionine, met-enkephalin is distinct from its sibling peptide leu-enkephalin. The proenkephalin precursor contains multiple copies of the met-enkephalin sequence, a layout documented in the repeated features of its UniProt record.
What Researchers Are Saying
Community Reports - Not Medical Advice
The following is aggregated from public forums, Reddit, and research communities. These are anecdotal reports from researchers only - not verified clinical data and not a recommendation of any kind.
Met-Enkephalin (also known as MENK, methionine enkephalin) is studied within the cognitive function and neuroprotection research community. Endogenous opioid pentapeptide studied for immune modulation, nociception, and cancer cell growth inhibition.
Last updated October 28, 2026
Research status: active. Met-Enkephalin appears across cognitive function and neuroprotection research forums and academic literature. Researchers note this compound falls in the cognitive category.
Last updated October 28, 2026
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