This page presents data on the content and variability of samples that were “sold as fentanyl” in order to provide some insights into unregulated fentanyl.
The first figure provides information on the content of samples sold as fentanyl over the past four quarters. Click on 'Samples sold as fentanyl' in the legend to turn on that series and see the total samples sold as fentanyl included in each quarter. For samples sold as fentanyl, we include both fentanyl itself and fentanyl analogues to be the "expected" drug. Additional data notes are at the bottom of this page and the details on drug categories are available here.
To explore the variability of samples we provide data in the next figure including the median number of substance results (the count of chemicals found in a given sample) and the median number of fentanyls and fentanyl precursors found. Higher numbers represent more chemicals being detected. As a further measure of variability, the standard deviation of the result count by quarter is shown, with higher numbers indicating more variability in the number of chemical results among samples in the quarter.
Data notes
Drug testing sites can do little about potential cross-contamination: The container a client used may or may not have been used before. Therefore, any unusual combination may be due to cross-contamination and not represent drugs actually sold together. For more details on drug categories named, click here. The metrics presented here include:
No expected drug: The percentage of samples with neither fentanyl nor fentanyl analogues.
No fentanyl: Samples with no fentanyl, which may or may not have had one or more analogues instead.
Analogues: Any substance in the fentanyl analogue (fentalog) class, which may be substantially weaker or stronger than fentanyl itself.
Strong analogues: Included in the Analogues category, this subcategory calls out those analogues believed to be at least 3 times as strong as fentanyl. As of this writing, this is almost entirely carfentanil, with one confirmed sample containing methyl fentanyl.
Strong sedative: See our xylazine page for more on this tranquilizer often added to fentanyl for sale. Medetomidine, an even stronger tranquilizer, began appearing in the local drug supply in May 2025.
BTMPS (Bis[2,2,6,6-tetramethyl-4-piperidyl]sebacate) is a chemical that appeared in drug checking samples in 2024. See our BTMPS page for more information.
The Other novel synthetic opioid (NSO) category is included in the Major unexpected drug category (below).
Major unexpected drug: Samples with methamphetamine, cocaine, other opioids, etc.
Minor unexpected drug: Includes minor stimulants, dissociatives, depressants, and hallucinogens.
SD result count: The standard deviation, a measure of variability, of each sample's count of unique chemical results.
Median result count: Median of the count of unique chemical results.
Median fentanyl-related result count: Median of the count of chemical results in the fentanyl, fentanyl analogue, or fentanyl precursor categories.
Medians are more stable measures of central tendency than averages. If quarter 1 ranges from 2 to 8 and quarter 2 ranges from 2 to 16, the median--the middle value--might be no different but the mean for quarter 2 will be pulled up by the presence of even a single extreme value (e.g., 16). The standard deviation would increase in quarter 2 in this example.
Using our interactive charts