CBD, short for cannabidiol, is the second most prevalent active ingredient in the Cannabis sativa plant, also known as cannabis or marijuana. This isolated compound does not produce a high when consumed, unlike smoking marijuana, which produces an intense psychoactive effect due to the presence of tetrahydrocannabinol (THC).

More recently, the use of CBD has surged as people turned to it as a way to enjoy the soothing and wellness effects of marijuana without the high. In 2020, the global CBD market was $2.7 billion and is projected to balloon $55 billion in 2028. But just because the market is now huge, that doesn’t mean that all CBD products are created equal.

Case in point, in a new study, researchers bought 80 different CBD products from online shops or stores in Kentucky and were shocked to find over 60% of them contained non-negligible amounts of THC. This is hugely concerning and potentially illegal in some states where cannabis is still illegal. People who have no tolerance to THC may become intoxicated through repeated use, as the psychoactive compound tends to accumulate in fat cells as the impure product is used over time. That could turn into a big problem if the user is driving or performs any motor task that could put their safety in danger.

The products tested by researchers at the University of Kentucky College of Medicine also included Epidiolex, which is the only CBD product approved by the FDA. The product is prescribed to help control epileptic seizures and its manufacturing is rigorously regulated, unlike the other CBD products on the market which are designated as supplements and have little oversight.

The researchers found that Epidiolex contains 0.022 milligrams of THC per milliliter, which, in this context, is an acceptable amount considering the manufacturing process. However, all but five of the impure CBD products identified by the researchers contained higher THC levels than in Epidiolex. Eleven products had THC concentrations greater than 1 milligram per milliliter, and one had 2 milligrams per milliliter, or almost 100 times more than Epidiolex.

“That’s worrisome because a lot of elderly people do take CBD and are taking a lot of other medications, and they could have high levels of THC in their product,” said Shanna Babalonis, an assistant professor of behavioral science at the University of Kentucky College of Medicine and author of the new study.

Ingesting THC even in trace amounts could potentially cause all sorts of trouble. In states like Washington, if a driver is found to have over 5 nanograms of THC per milliliter in their blood, they automatically get a DUI-cannabis. In many professions, such as those in the military, pilots, and athletes, there is often a zero-tolerance policy for THC. Many athletes take CBD because it helps with inflammation and might help some sleep better. But imagine getting banned from the Olympics, where THC is strictly forbidden no matter the amount found in the blood, after using a CBD product that you were repeatedly told doesn’t contain THC.

“I think that one of the key takeaways from this work is to say that the public needs to question whether there’s THC in their CBD products,” Babalonis said.

The major takeaway here is that not all CBD products are alike and consumers should be mindful that some of these oils and edibles may contain THC, in more or less considerable amounts. About 30% of the products tested by the researchers virtually contained no THC at all, so it is possible to make a pure product if the manufacturing and quality testing is done properly.

Considering the risks faced by consumers, the researchers call for stiffer regulation of CBD products. For now, the market is still the Wild West and consumers should buy CBD with caution.

“If you’re buying a drink at the grocery store, you would expect when it says there’s no alcohol in it, that there’s no alcohol in it,” Babalonis said. “You wouldn’t drink it expecting to feel some alcohol effects or maybe blow positive on a Breathalyzer. This is the same thing.”

The findings appeared in the journal Drug and Alcohol Dependence.