CBD Blocked Key Nicotine-Metabolizing Enzymes in a Laboratory Study

A 2023 laboratory study found that cannabidiol (CBD) can inhibit enzymes involved in nicotine metabolism, raising questions about how the cannabinoid might affect people who use both tobacco and CBD. The findings do not show that CBD reduces cigarette cravings or helps people quit, however, because the research was conducted using isolated enzymes and human liver microsomes—not in smokers.

The study, published in Chemical Research in Toxicology by researchers at Washington State University and Penn State University, examined CBD and its active metabolite, 7-hydroxy-CBD. The work was funded by the National Institute of Environmental Health Sciences, part of the National Institutes of Health.

Researchers focused on CYP2A6, the primary enzyme responsible for converting nicotine into cotinine, as well as CYP2B6 and several enzymes involved in the metabolism of nicotine’s metabolites. They tested the compounds in microsomes from genetically modified HEK293 cells and in human liver tissue.

In the laboratory assays, CBD inhibited CYP2A6- and CYP2B6-mediated nicotine metabolism. In preliminary screening experiments, approximately 1 micromolar concentrations of CBD reduced some metabolic reactions by about 50 percent. More detailed testing also showed inhibition of several nicotine-metabolism pathways at submicromolar concentrations under the experimental conditions.

These results suggest that CBD could produce a drug–drug interaction when used alongside nicotine or tobacco products. By slowing nicotine metabolism, CBD might change how long nicotine and its metabolites remain in the body. That could potentially influence nicotine exposure, tobacco use, or dependence—but the direction and clinical importance of any such effect cannot be determined from this study.

In particular, the research did not measure cigarette consumption, withdrawal symptoms, cravings, quit attempts, or abstinence. It also did not test whether CBD helps people stop smoking. The authors described the findings as potentially relevant to tobacco addiction and cessation strategies, but acknowledged that laboratory inhibition measurements do not by themselves establish a treatment benefit in humans.

That distinction matters because reducing nicotine metabolism would not necessarily make quitting easier. It could alter nicotine levels in ways that affect both the perceived effects of nicotine and exposure to the drug. The consequences may also vary with CBD dose, product formulation, frequency of use, genetics, liver function, and other medications.

CBD products also have safety and quality concerns. The U.S. Food and Drug Administration notes that CBD can cause liver injury and interact with other medicines. Outside of an approved prescription product for certain seizure disorders, CBD products have not been evaluated by the FDA as smoking-cessation treatments.

For people trying to quit, established options remain the better-supported approach. The Centers for Disease Control and Prevention recommends counseling and proven cessation medications, including nicotine-replacement therapy, varenicline, and bupropion. In the United States, free help is available through 1-800-QUIT-NOW.

The Washington State University study provides a useful starting point for understanding how CBD and nicotine may interact in the body. Human clinical trials will be needed before researchers can determine whether CBD has any meaningful effect on cravings, cigarette use, or successful smoking cessation—and whether its potential benefits outweigh its risks.