A new research project looking at THC levels in different products on the Canadian market is once again highlighting the lack of reliably labelled dried cannabis flower.

The lead researcher involved in the project says this is a failure by Heath Canada to set and enforce reasonable variability limits on Cannabis Flower or pre-rolls, leading to a lack of credibility in the market domestically and internationally. 

Rob O’Brien, CEO and CSO at Supra Research and Development, an analytical testing lab in Canada that includes cannabis testing in its repertoire, says he worked with seven other labs across Canada to sample an array of cannabis products and compile the results. O’Brien has shared similar results on the subject in the past.

The goals, says O’Brien, were to more effectively highlight the extent of the problem in Canada and prove that analytical testing labs can accurately test cannabis without much deviation between them. 

While the issue of THC inflation is relatively well-known, one of the reasons some have suggested for a lack of enforcement of THC levels on dried flower is the level of deviation in results depending on the lab used. But what these results show, says O’Brien, is that different labs all testing the same or similar samples can still come up with results that are relatively close to each other. 

This is highlighted by the project’s findings, which showed not only the deviation between the posted THC levels on the label of a cannabis product but also the deviation in the results between those labs. Three to four labs would receive the same sample, and in most cases, their results came within the same range, showing that when these labs use the same methodology, they can arrive at relatively similar measurements.

“Clearly there have been suggestions that there are THC inflation problems in the Canadian and US marketplaces. And people have been trying to identify the source of that and fingers have been pointed in many directions, including the accuracy of labs in Canada,” says O’Brien.

“I think it’s undermining the whole industry in Canada and the US,” he adds. “I think it’s outrageous that these shenanigans are allowed to continue. Health Canada is partially responsible because they’re not enforcing reasonable limits. And this clearly shows that if they do set reasonable limits, Producers can be within 15% of label claim.”

How it worked 

The research, conducted by eight analytical testing labs in Canada, tested 16 different brands of 3.5 g dried flower products available in several provincial markets, four different brands of pre-rolls (non-infused), and 15 different brands of infused pre-roll flower product. 

Researchers used an allowable variance for the dried flower and pre-rolls of 25% and 15% for infused pre-rolls, similar to the allowable limit within federal cannabis regulations. Note: this means, for example, that a product labelled as having 30% THC could be over or under that number by 7.5 percentage points, or 23.5% THC or 37.5% THC.

More than half (nine) of the samples from the 3.5-gram dried flower SKUs were found to be more than 25% below the stated label claim, and two of those were more than 40% lower than the label claim. 

Meanwhile, only one of the four brands of non-infused pre-rolls was outside the 25% allowable range, with one sample coming in just 2.1% lower than the label. 

For the infused pre-rolls, only three samples were outside the 15% range, and none were outside the 25% range. 

None of the dried flower or pre-roll samples were above the stated label claim, while two infused pre-rolls showed results slightly above the label claim.

While some may point to the issue being devious labs, the resulting research paper, which O’Brien shared with StratCann, speculates the issue may have more to do with sample bias by producers who are selecting top colas or other high-THC flowers as their representative sample instead of sampling the finished product after it’s packaged.

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The fact that there was greater THC inflation and label inconsistency in the dried flower samples from the research project highlights this issue more, O’Brien says. Since pre-rolls are more likely to be homogenized as part of the manufacturing process, there is less variation between the label claim and the actual products. 

The issue is even more pronounced with infused pre-rolls, which are considered an extract under federal regulations and, therefore, subject to a strict 15% deviation allowance.

While a cannabis flower may have a certain level of THC at harvest or after drying and curing, the process of processing and packaging that flower results in a loss of Trichomes that significantly reduce the THC content, which is why he says these products should be tested after packaging rather than before. 

“While we cannot pinpoint the origin of the discrepancies, we can speculate that the label claims >30% higher than the actual Total THC concentration in the finished product may be using artificially high COA’s from a harvest rather than testing products after being handled and processed into the finished form,” says the paper. “Active cannabinoids are compartmentalized in fragile trichome structures that can easily be dislodged during mechanical processing. Non-processed flowers may have a higher amount of cannabinoids than processed flowers.”

Still, the paper doesn’t entirely discount the possibility that some labs are also inflating numbers. 

“Furthermore, there is also the probability that some labs are artificially generating high COA’s or that the producers are sending samples that are doctored. However, these possibilities can not be determined from this type of study.”

Three or four packages of each brand were obtained from cannabis stores in several provinces. These were then sent to a central lab, sorted, and randomly sent to the other labs involved in the study.

Although they’re not releasing the names of the specific brands they tested because they don’t want to harm any brand, O’Brien says the full data set will be shared with Health Canada and provincial cannabis distributors. The hope is that when producers with accurate label claims are contacted, they will permit the publication of their name to create positive news stories about this issue. 

More information about these results, including all participating labs, is expected to be released at a future date.

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