Hemopressin is a recently discovered endocannabinoid that acts as a CB1 inverse agonist (roughly meaning that it has the opposite action of THC at CB1 receptors). Most cannabinoid receptor ligands are lipids. However, hemopressin is the founding member of a new class of endocannabindoids: the peptide cannabinoids or PepCanns. As hemopressin actually has a higher affinity for CB1 than any other true cannabinoid, this justifies hemopressin being classified as an endocannabinoid. Hemopressin strongly suppresses pain sensation and eating and may counteract de-myelination in diseases like Multiple Sclerosis and therefore has considerable therapeutic potential.
Hemopressin is a breakdown product of hemoglobin, the protein that delivers oxygen throughout the body.