U-48800 is an opioid analgesic drug analog of initially U-47700, just added one methylene on the benzene ring; at the same time, 2,4-chlorophenyl replaced the 3,4-dichlorophenyl. U-48800 is selective for the µ–opioid receptor, having around 7.5 times the potency of morph in animal models. Research shows that the U-48800 has the same potency level as the original U-47700. Use for laboratory research only, not for human consumption.