Chocolate Can Throw Off Testing of Cannabis Edibles

SAN DIEGO, Calif. – At the American Chemical Society (ACS) Fall 2019 National Meeting and Exposition, being held through Thursday in San Diego, California, researchers are expected to present a study showing that chocolate compounds affect test results for cannabis edibles.

The study’s lead researcher, David Dawson Ph.D., was quoted on the ACS website and said, “My research focuses on cannabis potency testing because of the high stakes associated with it.


“If an edible cannabis product tests ten percent below the amount on the label, California law states that is must be relabeled, with considerable time and expense. But it’s even worse if a product tests ten percent or more above the labeled amount—then the entire batch must be destroyed,” Dawson explained.

The study was conducted at cannabis testing lab CW Analytical Laboratories located in Oakland, California. Dawson and the CW team had, over time, noticed “weird potency variations,” when testing cannabis edibles containing chocolate and that results could vary, depending on the amount of material being tested.

Researchers decided to focus on the “matrix effect” created when various compounds combine with Δ9-tetrahydrocannabinol, or THC—the psychoactive compound found in cannabis.

Size of test samples, varying amounts and types of chocolate, and various preparation methods were analyzed to observe the effects on THC levels in final test results. Researchers found the matrix effect was enhanced for edibles containing chocolate and that testing methodology also could have an affect.

“Simply changing how much sample is in the vial could determine whether a sample passes or fails, which could have a huge impact on the producer of the chocolate bars, as well as the customer who might be under- or overdosing because of this weird quirk of matrix effects,” Dawson said.

According to Dawson, an undetermined compound in chocolate seemed to be suppressing THC compounds in test results, potentially allowing more THC to be present in chocolate edibles than would be stated on labels.

Research will continue in an effort to determine which compounds in chocolate are creating the effects when combined with THC.

“Our best lead right now is that it has something to do with the fats, which makes sense considering that Δ9-THC is fat-soluble,” Dawson said.

ACS is the world’s largest scientific society and more than 9,000 presentations are expected during this week’s meeting. A press conference on this topic will be held Tuesday, August 27, at 11:00am PST, at the San Diego Convention Center, or can be viewed live on YouTube.