Beta endorphin is a neuropeptide that functions as an opioid in the brain and is involved in the regulation of various physiological processes, including pain signal transmission, mood, and stress. There are several synonyms for beta endorphin, such as Met-enkephalin, leu-enkephalin, and dynorphin. In addition to these, there are other related neuropeptides, including alpha endorphin and gamma endorphin, which also have opioid-like effects on the body. These neuropeptides act on different opioid receptors in the brain and play distinct roles in modulating pain and emotional responses. However, beta endorphin remains the most well-known and extensively studied opioid neuropeptide, with therapeutic potential in the management of pain and addiction.