US overdose deaths fall as fentanyl supply weakens, study finds

A study published in Science links a mid-2023 disruption in the illicit fentanyl supply — likely tied to tighter controls on precursor chemicals in China — with a fall of more than a third in US deaths involving synthetic opioids by the end of 2024.

A study in Science reports a sudden disruption in the illicit fentanyl supply beginning around mid-2023 that coincided with a sharp decline in US overdose deaths. Researchers say the timing matches tighter controls on fentanyl precursor chemicals reported in late 2023 and diplomatic pressure between the United States and China. Official data cited in the paper show lower fentanyl purity and fewer forensic lab seizures through 2024. The authors stop short of a definitive causal claim but present multiple lines of evidence linking supply changes to the drop in deaths. Key facts: - Researchers identify a supply shock beginning mid-2023 and link it to a rapid decline in US fatalities involving synthetic opioids, which fell by over one-third by the end of 2024. - U.S. Drug Enforcement Administration data cited in the study show average fentanyl powder purity peaked in early 2023 and then fell by more than half by the end of 2024, while forensic lab seizures dropped about 37% below their 2023 high. - Online discussions on Reddit mentioning a fentanyl "drought" increased starting mid-2023, providing supplementary signals about availability and quality in illicit markets. - Canadian data show opioid deaths also began to decline in the third quarter of 2023, and the paper notes differences in how Canadian and U.S. markets adapted; the authors point to reported Chinese measures in late 2023 to curb precursor exports and remove online supplier listings. Summary: The study indicates that a sudden tightening of the illicit fentanyl supply and lower drug potency likely contributed to the rapid fall in deaths involving synthetic opioids. The authors and cited data describe reduced purity and fewer seizures across 2023–24 and note parallels in Canada and reported Chinese controls on precursors. They also warn that supply shocks can be temporary and that incentives to restore illicit supply persist, leaving the durability of the decline uncertain.