Commercial Cannabis Labels Often Don’t Match Chemical Reality, Study Finds

The traditional classifications of sativa, indica, and hybrid-type cannabis might not actually tell consumers very much about what is in their product, new research suggests.

Published in the journal PLOS One, the new study looked at more than 90,000 cannabis samples from across six US states and found that current commercial cannabis product labels “do not consistently align with the observed chemical diversity” in the products themselves. This was true for both the broader labels of sativa, indica, and hybrid, but also for many individual cannabis strain names.

“Our findings suggest that the prevailing labeling system is not an effective or safe way to provide information about these products,” co-author Brian Keegan, an assistant professor of Information Science at the University of Colorado Boulder, said in a statement. “This is a real challenge for an industry that is trying to professionalize itself.”

Commercial labels are inconsistent at best

The general rule of thumb from cannabis consumers has long been that sativa cannabis strains are energizing, indica strains are sedating, and hybrids are an intermediate mix of the two. If this is true, then there should be some clear divisions visible when the chemical analysis results of different classifications are compared against each other.

The data analyzed in this study was provided by the Leafly data sharing program, where academics can access data and crowd-sourced metrics gathered by the cannabis technology firm. This includes official laboratory testing records, as well as consumer ratings and reviews that have been submitted to Leafly.

It is important to note that while Leafly did provide access to their records and a Leafly researcher did collaborate on the research paper, Leafly had no control over the study design and provided no funding for the project.

Cluster analysis done on the cannabinoid and terpene content data from more than 90,000 samples showed high amounts of intermingling. This means that the supposed divisions between sativa, indica, and hybrid-type cannabis strains do not appear to have any material chemical reality behind them.

In theory, commercial cannabis strain names should be even more distinct.

“A farmer can’t just pick up an apple and decide to call it a Red Delicious. A beer manufacturer can’t just arbitrarily label their product a Double IPA. There are standards. But that is not the case for the cannabis industry,” study co-author Nick Jikomes, director of science and innovation for Leafly, said in a statement.

However, comparing chemical composition across samples marketed under the same strain name returned mixed results. Some strains, such as Purple Punch, were relatively consistent, with 96 percent of products falling within the same broad cluster. On the other hand, strains such as Tangie were “consistently inconsistent”, with only around 60 percent of samples having the same broad chemical similarities.

“There was actually more consistency among strains than I had expected,” he said. “That tells me that the cultivators, at least in some cases, may not be getting enough credit.”

Terpenes may be a more reliable classifier

While the cannabis samples here did not fall into three neat categories of sativa, indica, and hybrid, the researchers did observe three broad categories based on the most prominent terpenes in each sample.

These clusters were largely high in either β-caryophyllene and limonene (Cluster 1), β-myrcene and ⍺-pinene (Cluster 2), or terpinolene and myrcene (Cluster 3).

“These results indicate that even a simplistic labeling system, in which THC-dominant samples are labeled by their dominant terpene, is better at discriminating samples than the industry-standard labeling system,” the researchers wrote.

These divisions by dominant terpenes are not a completely new concept. In 2018, researchers at Digipath Labs also uncovered three distinct clusters of strains organized by their terpene content.

“We were testing for 31 analytes, so 11 cannabinoids and 22 terpenes. When we looked at the terpene data, there were three distinct clusters, which got me very interested in looking more closely at what makes terpenes responsible towards the subtle physiological effects that people realize from these different strains, even though they all have the same high THC content,” Cindy Orser, PhD, chief scientific officer at Digipath, told Analytical Cannabis at the time.

“Because of people’s fascination with getting high, all the focus has been on THC, but this plant has been having remarkable effects for hundreds of years when it only had 3% THC - it’s been used through the centuries for medicinal purposes. There’s a lot more going on here,” she added.

Towards more reliable labeling

Based on their results, the researchers behind this new PLOS One study suggest that cannabis firms could consider moving away from this sativa and indica model and towards a cannabis labeling system similar to the nutrition facts labels used in food.

“It’s like if your cereal box only showed calories and fat and nothing else,” Keegan said. “We as consumers need to be pushing for more information. If we do that, the industry will respond.”

“The founding fathers of cannabis research call it a pharmaceutical cornucopia because it produces so many different chemicals that interact with our bodies in different ways,” Keegan added. “We are only scratching the surface.”

Such a future might not be too far away. The prestigious Emerald Cup awards have already implemented a terpene-based classification system powered by their partnership with SC Labs. The organizers of the Emerald Cup believe that putting a stronger focus on terpene content will help to reframe the conversation around craft cannabis and cannabis quality in a way that the current hyperfocus of the market on high THC content does not.

“What we’re looking at is which terpenes and cannabinoids are present in that plant or in that sample, and then we're also looking at the overall magnitude of those terpenes,” Josh Wurzer, the president of SC Labs, recently told Analytical Cannabis.

“There’s awards in each of the broad terpene categories, as well as the broad cannabinoid categories. And then we’re also looking at a novelty – so there’s a category where we’re going to see a lot of novel new strains that are relatively uncommon, and terpene profiles that are relatively uncommon.”