A 2017 study analyzed 84 CBD extracts from various brands and found that only 31 percent of them contained the amount listed on the packaging.
“It’s expensive for manufacturers to ensure the quality of their products,” explains Mike T. Nelson, Ph.D., a Minneapolis-based exercise physiologist who studies CBD. If they find a batch has too much THC (the federal threshold for THC content in products is 0.3 percent) or too little CBD, many companies will opt to push the items to market to avoid tossing thousands of dollars’ worth of merch.
Discrepancies between stated and actual contents aren’t the only problem. “Cannabis is a bioaccumulator, which means it absorbs whatever is present in the surrounding soil,” adds Laura Lagano, RD, co-founder of the Holistic Cannabis Academy health practitioner training program in Boulder. If your CBD oil came from plants grown in low-quality dirt, it could contain harmful toxins from pesticides and heavy metals that have long-term health effects.
The bottom line:
Before choosing a CBD product, check the brand's website to make sure the products are tested by third parties (which means they’re screened for CBD, THC, and soil-derived contaminants) and in several batches (which confirms multiple samples were evaluated for quality).