As cannabidiol (CBD) products become a fixture in American homes, a new FDA study has found that even low doses may quietly harm the liver in some users. Researchers conducted a placebo-controlled study with 201 healthy adults, giving some participants a common consumer dose of CBD for four weeks. While most saw no issues, about 5% showed significant elevations in liver enzymes—a sign of potential liver cell damage or inflammation, per NBC News. Women appeared more susceptible than men, and seven people withdrew from the study due to clinical signs of possible drug-induced liver injury. Notably, liver enzyme levels returned to normal within weeks of stopping CBD use.
Despite the boom in CBD sales—now a $1.9 billion industry—there remains little concrete evidence regarding the long-term safety or efficacy of these widely available products. Past studies have flagged liver concerns, especially at higher doses or when combined with other medications, but this latest research suggests even typical consumer amounts can pose a risk for some. Symptoms of liver injury can include abdominal discomfort, jaundice, and fatigue, but most cases in the trial, published Monday in JAMA Internal Medicine, were asymptomatic. Experts say this means users may be unaware of ongoing harm, and doctors should routinely ask about CBD use during checkups. Genetics may play a role in who is most at risk, and the study also found a link between liver issues and an immune response called eosinophilia.