Deaths caused by nitazenes, synthetic opioids hundreds of times stronger than heroin, may be higher than reported in the UK. The National Crime Agency found 333 deaths linked to nitazenes in 2024. But King’s College London researchers say this number could be underestimated by about one-third. Nitazenes were made as painkillers in the 1950s but stopped due to their addiction risks. The study showed these drugs break down quickly in postmortem blood samples, with only 14% of the drug typically found during toxicology tests. Researchers tested rats anaesthetised with nitazenes and compared the results with UK drug death data. They noticed extra deaths in Birmingham in 2023, hinting toxicology tests often miss nitazenes. Dr Caroline Copeland from King’s said, "If nitazenes are degrading in postmortem blood samples, then we are almost certainly undercounting the true number of deaths that they are causing." She stressed that inaccurate data means harm reduction strategies may fail, leaving preventable deaths unchecked. Synthetic opioid deaths are rising in the UK, with Scotland already warning of a drug death crisis linked to these powerful substances. Mike Trace, Forward Trust CEO, noted the findings support calls for better drug testing and overdose prevention. The UK government stated its commitment to reduce drug deaths and mentioned using specially trained dogs at borders to detect fentanyl and nitazenes. This research highlights hidden dangers from ultra-strong synthetic opioids and points to urgent need for improved testing and health services to save lives.