You’re probably not as high as you think you are. It turns out only 17% of medical “edibles” in Seattle, San Francisco, and Los Angeles feature packaging that accurately describes their tetrahydrocannabinol (THC) levels, according to a recent analysis in The Journal of the American Medical Association.

The study, paid for by the Johns Hopkins University School of Medicine, took 75 cannabis candies, drinks, and baked goods from 47 different brands and had them tested by the Werc Shop, a laboratory with a focus on cannabis. 66% of the products had less THC than they declared and 23% actually had more.

“What we have now in this country is an unregulated medical marijuana industry, due to conflicts between state and federal laws,” said Dr. Donald Abrams, chief of hematology and oncology at San Francisco General Hospital. Abrams was not part of the study, however.

44 of the 75 products also had detectable levels of cannabidiol (CBD), though only 13 of them had it labeled. The phytocannabinoid accounts for up to 40% of the plant’s extract and has wider usage in its applications than THC.

CBD and THC are typically the most concentrated chemical components of cannabis and are believed to primarily drive therapeutic benefit, says the study, which estimates 16% to 26% of cannabis-using patients consume edible products.

So next time you get a pot brownie, it might be wise to have a few more on deck, just in case.