(S)-()-MT-45 hydrochloride is primarily used in research settings to study its pharmacological properties, particularly its effects on the central nervous system. It has been investigated for its opioid-like activity, making it a subject of interest in understanding pain management and addiction mechanisms. Researchers utilize this compound to explore its binding affinity to opioid receptors and its potential analgesic effects. Additionally, it serves as a tool in neuropharmacology to examine the biochemical pathways involved in opioid signaling and tolerance development. Its application is strictly limited to laboratory studies, and it is not approved for therapeutic use in humans due to safety concerns and potential side effects.