In brief
- The Welsh service WEDINOS analyzed thousands of samples anonymously and free of charge between April 2025 and March 2026: 36.6% did not contain the substance the person believed they had purchased.
- For the first time, “orphines”—a family of highly potent synthetic opioids—were identified mixed with veterinary sedatives in samples sold as heroin.
- 43% of vape liquids sold as THC or CBD contained synthetic cannabinoids not listed on the label.
The Welsh public drug-checking program, WEDINOS (Welsh Emerging Drugs & Identification of Novel Substances), has published its annual report for the period of April 2025 to March 2026. The conclusion that has most resonated in the British press is simple: one in three buyers does not receive what they requested, and that gap between expectation and reality has widened with the arrival of a new family of synthetic opioids.
A free, no-questions-asked postal service
WEDINOS has been operating since 2013 and is managed by Public Health Wales. Anyone, inside or outside the United Kingdom, can mail a small sample of what they have purchased and receive the analysis results in a few days, providing no information other than an anonymous code. It is the same principle applied by harm reduction services in other countries: the more people check what they consume, the more accurate the map of the real market becomes, rather than the one advertised by those selling the substances.
Orphines where heroin was expected
The novelty of the report is the “orphines” (orphine analogues), a family of highly potent synthetic opioids related to the nitazenes that have been circulating in Europe for years. The WEDINOS team detected them for the first time, mixed with veterinary sedatives in samples that the submitter believed to be heroin. Rick Lines, head of the program at Public Health Wales, summarizes it this way: the data “demonstrate once again the continued volatility of illicit drug markets and the high level of substitution within the market.” The report adds that nitazenes remain present and that newly synthesized benzodiazepines have appeared, sold as diazepam—another category where the actual content can differ significantly in potency from the drug it mimics.
What this implies
These data are from Wales, not Spain, and the synthetic opioid market at play there—heroin cut with fentanyls and now with orphines—is not the one that predominates here, where heroin is less prevalent compared to cocaine, MDMA, or cannabis. However, the underlying pattern is of interest to any person who uses drugs: when a substance is more heavily policed or becomes scarce, the market does not disappear; it changes composition, often using compounds for which there is barely any clinical literature. It is the same mechanism that led to the emergence of cyanazenes, designed to evade the ban on nitazenes. For anyone planning to consume something purchased as an opioid, the standard harm reduction guidelines—starting with a minimal dose, not mixing with other depressants like alcohol or benzodiazepines, not using alone, and having naloxone on hand if possible—remain valid, with the caveat that the label “heroin” no longer guarantees knowledge of what is inside. The other finding in the report, that 43% of THC or CBD vapes contained undeclared synthetic cannabinoids, serves as a reminder that the problem of unknown composition is not limited to opioids: it also extends to products sold as legal and harmless.
Source
- Public Health Wales / NHS Wales. Powerful new synthetic opioids identified by Welsh drug testing programme reveals increasingly unpredictable illicit drug market. Public Health Wales, August 26, 2026.
Educational content written from a harm reduction perspective and with respect for individual freedom. It is not a substitute for advice from a healthcare professional and is not intended to encourage or condemn any drug use.
