If those cannabis potency numbers on the outside of the bag seem too good to be true, they probably are, according to a new study of products in Colorado from the University of Northern Colorado.
The study analyzed 23 samples of flower purchased from 10 different retailers on Colorado’s Front Range and compared the results to the potency reported on the packaging. On average, the scientists found that observed THC potency was between 23.1% and 35.6% lower than the reported values.
Overall, about 70% of the samples were more than 15% lower than the THC potency numbers reported on the label, with three samples having only half of the reported maximum THC potency.
“Our results clearly demonstrate that retail cannabis flower THC potency is significantly inflated in samples purchased in Colorado,” write the report’s authors. “Given the numerous recent reports and lawsuits questioning THC potency reporting, it is likely that this is an industry wide problem.”
Though the report does not state the exact cause of the discrepancy between numbers, it does note that “a lack of standardized testing protocols, limited regulatory oversight and financial incentives to market high THC potency likely play a significant role.”
The 23 samples used in the study were mostly gathered from dispensaries in Denver, Garden City and Fort Collins. The samples were assigned a random number and taken to a third-party lab (Mile High Labs in Loveland) for total THC percentage by dry weight testing using high performance liquid chromatography (HPLC).
The report notes that Colorado, like all legal states, requires potency testing and labeling, but does not provide a clear set of testing standards or protocols. However, customers often use the numbers to drive purchases and they factor heavily into pricing, leading to cultivators “lab shopping” for those that produce the highest results. In Washington, for example, two labs have had licenses revoked, while lawsuits have been filed in Arkansas and California, according to the study.
— Brian Beckley