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Study Reveals Inaccurate Labeling of Marijuana as Hemp

NCJ Number
Police Chief
Date Published
October 2022

The National Institute of Justice (NIJ) funded the National Institute of Standards and Technology (NIST) to develop and validate extraction protocols and analytical methods to measure the amounts of THC, tetrahydrocannabinolic acid (THCA), and total decarboxylated THC in plant material.



The NIST researchers procured 53 hemp samples in plant form from five different commercial online sources. The online hemp vendor websites included a general declarative statement indicating that their products are hemp as defined under federal law. The statements disclose, “All products contain less than 0.3 percent THC” or, similarly, “Products are lab tested to ensure their THC content is less than 0.3 percent.” Researchers screened the samples for THC-related compounds using a thoroughly evaluated and peer-reviewed extraction procedure combined with a liquid chromatography photodiode array method for the analysis of cannabis plant samples.[3] The method essentially separates the different chemicals in a sample and displays them visually as chromatograms, which can then be compared to the chromatograms of known standards.[4] The amplitude of the peaks in the chromatograms can be used to calculate the amount of the chemical found in the total sample. Analyses indicated that of the 53 samples examined, 49 were incorrectly labeled as hemp because they technically fit the federal classification of marijuana (Figure 2). Of the 34 “hemp” samples obtained from Vendor 1, only two fit the federal classification of hemp as determined by total THC; the remaining 32 samples fit the federal classification of marijuana.[5] Of the eight samples from Vendors 2 and 3, none of the “hemp” samples examined should be classified as hemp—all should technically be marijuana. And of the 11 “hemp” samples examined from Vendors 4 and 5, only two samples fit the federal classification for hemp, while nine were technically marijuana. Of the inaccurately labeled samples, virtually all had total THC concentrations under 1 percent but above the legal threshold of 0.3 percent. Although these results cannot be taken as indicative of the entire field of commercial hemp products, they validate the notion that at least some products that are marketed as hemp (and appear official and reliable from a scientific point of view) can be legally classified as marijuana.[6] These products pose a particular challenge for labs attempting to quantify small amounts of THC, as well as consumers who may be unaware of what is contained in the product.

Date Published: October 1, 2022