Dermorphin is a naturally occurring opioid peptide originally isolated from the skin of South American frogs (Phyllomedusa species). It acts as a potent agonist of the mu-opioid receptor, offering analgesic (pain-relieving) effects far more powerful than morphine in animal studies. It is composed of seven amino acids and is considered highly selective for the mu-opioid receptor, which plays a key role in pain modulation, reward, and mood regulation.