Do labels accurately reflect THC content of medical marijuana edibles?
December 2, 2015, 10:34 pm
Cannabinoid Dose and Label Accuracy in Edible Medical Cannabis Products. Vantrey R et al. JAMA 2015 Jun 23/30:2491-2493.
Titrating the dose of edible marijuana is difficult for a number of reasons, including differing rates of absorption and unpredictable metabolism involving active metabolites.
In addition, some states that have legalized medical marijuana have not instituted stringent monitoring and regulation to assure that the dose listed on the package is consistent with the actual amount of THC and other cannabinoids in the product. The authors of this interesting study collected samples of different edibles (candies, baked goods, and beverages) from dispensaries in San Francisco, Los Angeles, and Seattle. They crushed or mixed each product and tested 2 sample from each for THC content. If the 2 samples from each product differed by more than 10%, the content of the entire product was measured. Products were considered accurately labeled if the THC content was within 10% of that listed on the label.
Of a total of 75 products tested, only 13 (17%) were accurately labeled. Some over-labeled products contained virtually no THC, while other under-labelled products contained as much as 55% more THC Than indicated on the package.
Note that the results assume that THC is spread homogeneously throughout the product, which is unlikely to be true in all cases.
Note also that the authors did not study samples from Colorado, which probably has more stringent regulations than California or Washington State. Colorado requires that edible cannabis products contain no more than 100 mg of THC, and earlier this year mandated that products be easily broken up into pieces of no more than 10 mg each. However, to my knowledge, they have postponed plans to test edible products for homogeneity — a much more difficult and costly analysis.
To read my Emergency Medical News column about edible marijuana entitled “Four Things Maureen Dowd Should Have Known About Cannabis Before Going to Denver,” click here.