The Netherlands: Trimbos THC Monitor 2025 – THC levels and pricing trends*
On 21 January 2026, the Trimbos Institute published the 26th THC Monitor. It shows that in 2025 the average THC level of both the most-sold and the strongest Dutch-grown cannabis (“nederwiet”) in Dutch coffeeshops was higher than in 2024. The Trimbos Institute has been monitoring THC levels in coffeeshop cannabis every year since 1999, on behalf of the Dutch Ministry of Health, Welfare and Sport (VWS). For this monitor, cannabis samples were purchased from a sample of 50 out of the 565 coffeeshops in the Netherlands and then analysed in a laboratory for active substances.
*Dutch-grown cannabis (“nederwiet”): THC higher in 2025 than in 2024*
Trimbos defines “nederwiet” as cannabis presumed to be produced in the Netherlands. In its news release, Trimbos summarises its findings under the headline “THC levels in nederwiet have increased over the past three years.”
– In 2025, the most-sold nederwiet had an average THC level of 15.6%.
– The nederwiet that coffeeshops described as the strongest contained an average of 17.4% THC.
– Trimbos reports that the THC levels of the most popular and the strongest nederwiet varieties were comparable in 2025.
– Trimbos also reports that average THC levels in 2025 were higher than in 2024.
– The average THC level of the most-sold nederwiet rose from 13.8% in 2024 to 15.6% in 2025.
– The average THC level of the “strongest” nederwiet rose from 14.7% in 2024 to 17.4% in 2025.
*Hash: on average higher THC than cannabis flower*
For hash, Trimbos reports higher average THC levels than for nederwiet. Imported hash contained an average of 23.0% THC. Hash made from Dutch-grown cannabis (“nederhasj”) averaged 23.7% THC and did not differ significantly from imported hash. Trimbos also notes that imported hash is more widely available than nederhasj. Imported cannabis flower is sold by very few coffeeshops nowadays and had an average THC level of 5.6% in this measurement.
*CBD: virtually absent in nederwiet, higher in hash*
The monitor also discusses CBD. Trimbos describes that all categories of nederwiet contained very little CBD, and reports that the median (most common) CBD values for the most popular and strongest nederwiet varieties were 0% and 0.1% respectively. Hash traditionally contains more CBD than cannabis flower, and Trimbos reports that this is still the case. Trimbos reports a median CBD level of 1.5% for imported hash and 1.0% for nederhasj. Trimbos also reports that the long-term decline in CBD levels in imported hash started some time ago and may be explained by a further shift away from traditional hash-making methods towards methods using nederwiet-like plants. In a separate analysis, the report notes that “modern” imported hash (high THC, low CBD) and “traditional” imported hash (high THC and CBD) cannot be distinguished from each other based on product names.
*Prices: stable, but “strongest” nederwiet is more expensive*
Trimbos reports that prices are stable. Although Trimbos describes the potency of the strongest and most popular nederwiet as comparable, the strongest varieties were on average more expensive than the most popular ones. Trimbos reports an average price of €12.57 per gram for the strongest nederwiet versus €11.33 per gram for the most-sold nederwiet. As in the previous year, Trimbos could not demonstrate a relationship between THC levels and price for hash in 2025, while it did find such a relationship for cannabis flower.
*Trend interpretation: new measurement method since 2023*
Trimbos also includes a caveat about interpreting trends over time. In 2025, the chemical analysis of cannabis samples was conducted for the third time using the newer, more accurate HPLC-UV method. Trimbos states that differences compared with the years before the switch in 2023 cannot be used to identify or interpret trends, and that it will take the coming years to determine whether there are systematic changes.
*The regulated cannabis experiment (EGC): status and baseline findings*
In the same THC Monitor, Trimbos also describes the “Closed Coffeeshop Chain Experiment” (Experiment Gesloten Coffeeshopketen). Trimbos reports that after a transition phase, regulated cannabis (legally grown and quality-controlled) is available in all participating municipalities. Trimbos states that on 7 April 2025 the experiment phase officially started, that it will last four years, and that participating coffeeshops may only sell regulated cannabis products during this period. Trimbos also states that it is part of the research consortium monitoring the progress and effects of the experiment.
Trimbos refers to findings from earlier research within the experiment (the baseline measurement). This included, among other things, that coffeeshop menus contained more cannabis flower products than hash products, that the price difference between hash and cannabis flower was not significant in that analysis, that almost all coffeeshops sold joints but around 30% sold joints without tobacco, that around 35% sold edibles (with the note that it is unclear whether these are the permitted variant made with “raw, unprocessed cannabis”), and that around 25% of coffeeshops sold CBD cannabis flower or CBD hash. Trimbos also reports that future EGC reports will include chemical analyses of cannabis products and that these results will be compared with the THC Monitor.
*Regulated samples in the THC Monitor (label deviations in 4 out of 8 samples)*
Finally, Trimbos reports that most samples in this THC Monitor were not grown within the regulated experiment and were therefore not quality-controlled in terms of chemical composition. However, the same monitor states that eight cannabis flower samples were purchased that had been grown under the regulated experiment. Trimbos reports that in four out of these eight samples the measured THC level deviated by more than 30% from the label, and that in all cases the measured THC level was lower than stated on the label. Trimbos explicitly notes that this is not a representative sample and that the THC Monitor is not intended as a quality assessment of regulated experiment products.
I think it is important to emphasise that the figures in this THC Monitor do not mean that nederwiet has suddenly become “extremely stronger” overnight, but Trimbos does report a clear increase compared with 2024: the most-sold nederwiet rose from 13.8% to 15.6% THC, and the “strongest” nederwiet rose from 14.7% to 17.4% THC. At the same time, Trimbos reports that the THC levels of the most popular and the strongest nederwiet varieties were comparable in 2025, meaning that a large gap between “regular” and “top segment” products does not follow directly from these measurements. Trimbos also stresses that long-term trend interpretation is difficult, because since 2023 a newer, more accurate analytical method has been used and differences with earlier years cannot be used reliably. Finally, the same monitor also notes that in a small number of regulated cannabis flower samples from the regulated experiment, the measured THC levels were sometimes clearly lower than the label indicated, with Trimbos explicitly stating that this was not a representative sample.
*Who of what is Trimbos and what is the THC Monitor?*
The Trimbos Institute is a Dutch research and knowledge institute working on topics including mental health, addiction, and substance use. The THC Monitor is Trimbos’ annual study of THC (and related substances such as CBD) in cannabis products sold through Dutch coffeeshops. It has been carried out every year since 1999, commissioned by the Dutch Ministry of Health (VWS).
