CBD May Slow Nicotine Breakdown
A 2023 study from Washington State University found that cannabidiol (CBD) and its active metabolite, 7-hydroxy-CBD, can inhibit enzymes involved in nicotine metabolism. The findings point to a possible interaction between CBD and tobacco use—but they do not show that CBD helps people quit smoking.
Published in Chemical Research in Toxicology, the study examined nicotine metabolism in human liver microsomes and laboratory cell systems engineered to produce specific metabolic enzymes. The researchers focused on cytochrome P450 2A6, or CYP2A6, the primary enzyme responsible for converting nicotine into cotinine.
Nicotine is rapidly cleared from the body, with a typical half-life of roughly one to two hours. Because CYP2A6 metabolizes most nicotine in smokers, differences in the enzyme’s activity can affect how often a person smokes and how much nicotine they consume. The Washington State team found that CBD inhibited CYP2A6-mediated metabolism of nicotine and cotinine in both recombinant enzyme systems and human liver microsomes. The CBD metabolite 7-hydroxy-CBD produced similar effects.
The study also identified inhibition of several other enzymes involved in nicotine metabolism, including CYP2B6 and UGT1A9. However, the strength of these effects varied by enzyme and experimental conditions. The reported concentrations came from laboratory assays, and the researchers noted that results from in-vitro experiments do not reliably predict what will happen in people.
That distinction is important. The study did not measure cigarette consumption, nicotine cravings, withdrawal symptoms or quit rates. It also did not demonstrate that CBD would reduce exposure to the thousands of harmful chemicals in cigarette smoke. A slower rate of nicotine breakdown could theoretically alter nicotine levels after smoking, but whether that would lead someone to smoke fewer cigarettes—or instead change the pattern of nicotine use—requires controlled human research.
The study builds on earlier research suggesting that reduced CYP2A6 activity may be associated with lower cigarette consumption. It also follows a small clinical trial in which an inhaled CBD product was associated with fewer cigarettes smoked. Those findings are not enough to establish CBD as a smoking-cessation treatment, particularly because different products, doses and delivery methods can produce very different CBD exposures.
CBD may also affect the way other medications are processed. The U.S. Food and Drug Administration’s guidance on CBD warns about potential drug interactions and liver-related risks. Apart from the prescription drug Epidiolex, the FDA has not approved CBD products to treat smoking, nicotine dependence or other common conditions.
For people trying to stop smoking, established options include counseling, nicotine-replacement therapy and prescription medications. The federal Smokefree program’s quitting guidance describes medications that can ease withdrawal symptoms and make cessation more manageable.
Further studies will be needed to determine whether CBD meaningfully changes nicotine levels in smokers, what doses would be required, whether it affects cravings or cigarette consumption, and whether the potential benefits outweigh its risks. For now, the Washington State research is best understood as evidence of a possible drug–drug interaction—not proof that CBD can help people quit smoking.
