A comprehensive analysis by Australia’s National Drug and Alcohol Research Centre has revealed alarming trends in the online availability of nitazenes, a class of dangerous synthetic opioids never approved for medical use.

Between September 2021 and August 2025, researchers identified 5,945 nitazene listings across 37 cryptomarkets—online platforms where criminals trade illicit substances. While these synthetic opioid advertisements represented just 0.16% of all drug listings monitored, their presence signals growing concerns about these exceptionally potent substances.

Supply Chain Shifts from Asia to North America

The study uncovered a significant geographical shift in the supply chain. Initially, Asia—particularly China—dominated as the primary source region for nitazene listings. However, by late 2023, North America, predominantly the United States, had become the main origin point for these illicit offerings.

Three-Quarters of Listings Target Australia

Perhaps most concerning for Australian authorities: three-quarters of all nitazene listings advertised delivery to Australia, though this proportion fluctuated considerably throughout the monitoring period, ranging from 34% to 95%.

Most Common Variants Identified

Researchers identified several nitazene variants appearing most frequently on cryptomarkets. Isotonitazene, protonitazene, and metonitazene emerged as the dominant compounds during the four-year study period.

The landscape of available synthetic opioids evolved substantially over time. While substances like etodesnitazene and metonitazene became less prevalent, newer variants including N-desethyl protonitazene and isotonitazepyne gained prominence in marketplace listings.

Abandoned in 1950s, Now Resurgent

Originally developed during the 1950s, nitazenes were abandoned due to serious safety concerns and never received medical approval. Their recent resurgence in illicit production has contributed to increasing health harms globally, with detections and related incidents rising across multiple countries, including Australia.

The Drug Trends monitoring program has systematically tracked cryptomarket activity since February 2014, providing vital intelligence on emerging substance threats in the digital marketplace.

Source: UNSW