Buyer beware: Study shows cannabis labelling can be misleading

The terms indica and sativa are frequently applied to cannabis and are widely believed to be associated with distinct aromas and psychoactive effects. But Dalhousie researchers and their international partners who analyzed the genetic and chemical makeups of hundreds of cannabis samples have demonstrated these labels are poor predictors of a sample’s genetics and chemistry.

“Breeders label their cannabis strains using the terms indica and sativa. Retailers then rely on these labels to market their products, and consumers believe these labels are meaningful. But there is now broad scientific consensus that the current use of indica and sativa is misleading,” says Dr. Sean Myles, an associate professor in the Faculty of Agriculture.

“These labels are simply not reliable indicators of a plant’s genetic or chemical composition.”

What's in a name?

Cannabis' faulty labelling system likely arose at least in part due to its long history as an illegal substance, leading to a lack of information on plant pedigrees and no regulated naming conventions.

“If Pinot Noir appears on a bottle of wine, a consumer can be confident the wine is made from Pinot Noir grapes. Unfortunately, cannabis consumers cannot have this confidence — labels and strain names do a poor job of informing consumers about what they are consuming,” says Dr. Myles.

Dr. Myles and researchers from Wageningen University & Research and Bedrocan International, a medicinal cannabis company based in the Netherlands, recently published their findings in a scientific paper published in the journal Nature Plants.

The research team also determined the creative names given to cannabis strains, like Lemon Haze and OG Kush, are poor indicators of a strain’s chemistry and genetics. They found pairs of strains with the same name are often just as different genetically and chemically as pairs of strains with different names.

“Cannabis is unlike other valuable crops in that its naming conventions are highly unreliable. For patients consuming cannabis as medicine, this is particularly concerning,” says co-author Robin van Velzen, a lecturer at Wageningen and a plant scientist at Bedrocan. “There is now broad scientific consensus that an evidence-based naming convention is required for the cannabis industry.”

Understanding cannabis aromatics

While the researchers demonstrated contemporary cannabis labelling poorly describes the genetics and chemistry of samples overall, they did find a weak signal in the data suggesting the sativa/indica distinction may be driven by a small number of aromatic compounds, called terpenes.

Cannabis strains labelled as sativa had higher concentrations of terpenes that have tea-like and fruity aromas, while indica samples generally had higher concentrations of terpenes that smell earthy. This distinction in aroma between sativa and indica is consistent with reports by recreational users.

To explore this further, the researchers combined their chemical information with genomic data and identified a small number of regions in the cannabis genome that likely contribute to the earthy aroma associated with the ‘Indica’ label.

“Breeders and growers may be labelling their cannabis strains rather subjectively based on a small number of aromatic compounds that are under genetic control,” says Dr. Myles. “But overall, our evidence-based approach suggests consumers should not rely on cannabis labels to inform them of what they are consuming.”