Medical Cannabis Products in Massachusetts May Be Inaccurately Labeled

In the US state of Massachusetts, medical marijuana is not always as it seems. Many medical products, researchers say, seem to differ greatly from the contents of their labels.

According to a new study published in JAMA Network Open, up to a third of supposedly CBD-dominant cannabis products sold in Massachusetts may not contain any CBD at all.

Checking the label

To make their conclusions, the researchers from Massachusetts General Hospital analyzed urine samples from 97 patients who were enrolled in a clinical trial of the effects of medical cannabis for anxiety, depression, pain, and insomnia. Samples were provided within 48 hours of a patient consuming a product from a licensed dispensary and analyzed using high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS).

Vaping was the most popular medium of cannabis consumption, but most participants used products infrequently (less than monthly).

The researchers found that, among patients who used CBD-dominant products, there were no detectable CBD metabolites in 10 samples (30.3 percent). This proportion of “missing” CBD metabolites was even higher among patients who used products with advertised equal amounts CBD and THC; 20 urine samples (37 percent) showed no signs of CBD.

THC, on the other hand, did turn up where it shouldn’t have. The federally illegal cannabinoid was detected in 26 urine samples (78.8 percent) from participants who only used CBD-dominant products.

“People are buying products they think are THC-free but in fact contain a significant amount of THC,” Jodi M. Gilman, PhD, the paper’s lead author and an investigator in the Massachusetts General Hospital’s Department of Psychiatry, said in a statement. “One patient reported that she took a product she thought only contained CBD, and then when driving home that day she felt intoxicated, disoriented and very scared.”

But not every medical product at odds with its urine sample was necessarily mislabeled, according to Gilman. She and her colleagues also found that nearly 1 in 5 urine samples from those who vaped their cannabis contained no detectable cannabinoids whatsoever. So what happened to the cannabinoids? Well, the researchers surmised that the vaping devices may not have heated the cannabis products appropriately, which could explain the perplexing urine results.

Gilman and her colleagues also noted that their conclusions are further limited by the study’s scope; the cannabis products themselves were not analyzed and individual differences in patients’ rates of absorption and metabolism were not accounted for.

However, the study isn’t the first to claim that medical cannabis products may be mislabeled. In a study published in 2015, researchers directly analyzed 75 medical edibles sourced from California and Washington and found that 17 percent were accurately labeled, 23 percent were under-labeled, and 60 percent were over-labeled with respect to THC content.

“A lot of questions about the content of the products and their effects remain,” Gilman added in her statement. “Patients need more information about what's in these products and what effects they can expect.”