Experts believe breakthrough in US fentanyl crisis may have started in China

"The question is why was there a supply shock. And most indicators point to China. On returning to the White House, Trump made fentanyl a foreign policy priority and quickly designated the criminal groups trafficking it as foreign terrorist organisations while slapping tariffs on countries involved in its supply chain including China, the main source of fentanyl precursors, many of which are basic chemicals with legitimate uses."

"But by the summer of 2023 during the Biden administration overdose deaths at the national level had already begun to fall. By November 2025, they were down by more than a third. Investigators are still trying to unpick the factors behind the fall, but one theory put forward by Humphreys and his co-authors in a recent study published by Science links it to interventions in China that may have caused a long-lasting disruption to the fentanyl supply chain."

"The authors point to a dramatic fall in the purity of fentanyl being seized by US law enforcement from May 2023 to the end of 2024 the latest data publicly available which correlates with the fall in overdose deaths. There was a similar fall in purity in Canada, which is a distinct fentanyl market, suggesting the cause might originate where they both source their"

The US and China remain in conflict over fentanyl, with the US accusing China of not stopping chemical precursor sales and China suggesting the US shifts blame for its own drug problem. Despite ongoing tensions, overdose deaths in the US began falling by summer 2023 and were down by more than a third by November 2025. Investigators are examining why deaths declined, and one theory links the change to interventions in China that disrupted the fentanyl supply chain. A key indicator is a supply shock marked by a dramatic drop in the purity of fentanyl seized by US law enforcement from May 2023 through the end of 2024. A similar purity decline occurred in Canada, pointing to a shared source region for precursor supply.

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