Uncomfortably High: Testing Reveals Inflated THC Potency on Retail Cannabis Labels

Legal Cannabis products in the United States are required to report THC potency (total THC % by dry weight) on packaging, however concerns have been raised that reported THC potency values are inaccurate. Multiple studies have demonstrated that THC potency is a primary factor in determining pricing for Cannabis flower, so it has an outsized role in the marketplace. Reports of inflated THC potency and "lab shopping" to obtain higher THC potency results have been circulating for some time, but a side-by-side investigation of the reported potency and flower in the package has not previously been conducted. Using HPLC, we analyzed THC potency in 23 samples from 10 dispensaries throughout the Colorado Front Range and compared the results to the THC potency reported on the packaging. Average observed THC potency was 14.98 +/- 2.23%, which is substantially lower than recent reports summarizing dispensary reported THC potency. The average observed THC potency was 23.1% lower than the lowest label reported values and 35.6% lower than the highest label reported values. Overall, ~70% of the samples were more than 15% lower than the THC potency numbers reported on the label, with three samples having only one half of the reported maximum THC potency. Although the exact source of the discrepancies is difficult to determine, a lack of standardized testing protocols, limited regulatory oversight, and financial incentives to market high THC potency likely play a significant role. Given our results it is urgent that steps are taken to increase label accuracy of Cannabis being sold to the public. The lack of accurate reporting of THC potency can have impacts on medical patients controlling dosage, recreational consumers expecting an effect aligned with price, and trust in the industry as a whole. As the legal cannabis market continues to grow, it is essential that the industry moves toward selling products with more accurate labeling.