The Rapid Spread of a Novel Adulterant in the US Illicit Drug Supply—BTMPS

The US drug overdose crisis remains a leading cause of preventable death, driven by an increasingly unpredictable illicit drug supply. In recent years, novel adulterants, such as xylazine and medetomidine—α-2 adrenergic receptor agonists and central nervous system depressants—have become widespread, complicating clinical management and public health surveillance.1 Now, another unexpected substance has surfaced: bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate (BTMPS), a hindered amine light stabilizer used as a UV protectant in plastics and adhesives. Unlike previous adulterants, BTMPS has no known sedative or psychoactive effects, raising critical questions about how and why it has infiltrated the US illicit drug supply.2 Further, BTMPS is neither intended nor approved for human use and has never been studied in humans, leaving its toxicological profile and clinical implications largely unknown.3 In this Viewpoint, we describe BTMPS’ spread across the US, explore key hypotheses for its rapid emergence, assess potential health risks, and outline ongoing public health response needs.