Slight THC increase, emergence of semi-synthetic cannabinoids

As a supplement to the annual evaluations, the DIZ publishes evaluations of the analyzed cannabis samples every six months.

Figures and averages

In the first half of 2023, a total of 192 cannabis samples were handed in for analysis at the Drug Information Center (DIZ) Zurich. 127 samples were cannabis flowers, 46 samples were hashish and 17 samples were other cannabis products such as oils, liquids, edibles (gummy bears, sweets, etc.) and dabs (cannabis concentrate).

In the following, the results of the last years are shown in each case in proportion (2022/2021).

The flower samples contained an average value of 13.9% (13.3%/13.0%) THC. The average content of CBD was with 0.33% (1.1%/0.9%) lower than in the last evaluations. This can be further illustrated by the example of the flower sample with the highest CBD content. In the past years, these contained 14.5% and 12.3%, respectively; in the first half of 2023, the flower sample with the highest CBD content contained only 1.01%.

The hashish samples contained an average value of 25.75% (24.4%/19.6%) THC. The average content of CBD was with 1.03% (1.2%/4.2%) again at a low value as in 2022. It was obvious that the sample with the highest THC content (59.2%) was significantly higher than the samples with the highest active ingredient content (49.9%/49.5%).

Other ingredients

Of the 192 samples, 14 contained unexpected ingredients.

Synthetic cannabinoids

Fortunately, the trend continued that only a few samples were contaminated with synthetic cannabinoids. Of the total of 192 samples submitted in the first half of 2023, only two samples (1%) were affected. In 2022, 2.8% and in 2021 10% of all samples were contaminated.

On the other hand, there is an increase in semi-synthetic cannabinoids (delta-8-THC and HHC). Semi-synthetic cannabinoids, unlike fully synthetic cannabinoids, can be obtained from natural cannabinoids by chemical processes.

∆8 -THC (Delta-8-THC)

Delta-8-THC was detected in 7 samples (3 oil, 2 hashish, 1 flower and 1 wax sample)

Delta-8-THC is a psychoactive cannabinoid that produces a similar intoxicating effect as delta-9-THC (the "classic" THC), but is less potent. In all likelihood, delta-8-THC is primarily a byproduct produced during the chemical conversion of CBD (cannabidiol) to delta-9-THC. This conversion is likely used to create delta-9-THC from low-noise CBD products, or pure CBD. The resulting mixture of delta-8-THC and delta-9-THC can then be applied to CBD products for sale on the black market as natural and THC-containing cannabis products. The byproducts produced during the conversion process are expected to be toxic. Since synthesis by-products are often not completely separated by the manufacturers and are thus consumed by the consumers together with delta-9-THC and delta-8-THC on cannabis products, an unknown health risk is taken when consuming them. No clinical studies are available on the short- and long-term side effects of delta-8-THC and the synthesis byproducts. For more information on Delta-8-THC, click here.

HHC (hexahydrocannabinol)

HHC was detected in 4 samples (3 hashish, 1 oil). HHC is a THC derivative that occurs only in traces in the cannabis plant. It is therefore primarily obtained by hydrogenation of THC (for example, from cannabis extracts), but can also be produced fully synthetically. Studies from the early 1940s indicate that HHC is about half as potent as ∆9-THC, but otherwise has similar effects. According to user reports, the spectrum of effects is similar to that of ∆9-THC, but in higher doses, the substance is said to have an effect that is perceived as unpleasant. Little is known about the risks and side effects of HHC, and there are no data on the long-term effects of its use. More information on HHC can be found here.

Züri CAN pilot project

Based on the newly created legal requirements, the City of Zurich and the University of Zurich have prepared the study "Züri Can - Cannabis with Responsibility". The study examines the effects of obtaining selected cannabis products from controlled cultivation under regulated conditions on the consumption and health of participants. In addition, different models of the regulated supply of cannabis will be compared with each other. DIZ Zurich will be one of the sales outlets from August 22, 2023. Besides us, 10 pharmacies and 10 social clubs will complete the offer.

For more information and the detailed description of the study, click here.


No items found.

Article from

Mentioned substances

Matching warnings

This might also interest you