A recent publication from Millennium Health, an organization focused on drug testing, warned that the concentration of fentanyl on the West Coast has reached “all-time highs,” threatening to reverse the recent decline in overdose deaths. To arrive at this worrying conclusion, Millennium Health “analyzed more than 976,000 clinical [urine drug test] results collected from January 2024 through June 2026 to evaluate changes in fentanyl detection, normalized fentanyl concentrations, and the detection of heroin and xylazine in the population using fentanyl.”
Drawing on its results, the organization explained that “in the West, xylazine and heroin detections spiked in 2024 as fentanyl concentrations fell, but reversed as fentanyl concentrations rose dramatically through early 2025,” adding that “fentanyl concentrations then surged to all-time highs from late 2025 through mid 2026.”
Source: Millennium Health
They pointed to a fentanyl supply shock as helping to explain the decline in fentanyl-involved overdose deaths in 2024. The publication continued: “the rapid rise in overdose deaths in the West from late 2024 through early 2025 may reflect a rebound in fentanyl purity and/or potency.”
In comparison, Millennium Health noted that the declines in the concentration and detection rates of fentanyl on the East Coast have “have largely persisted through mid 2026.”