CBD-Associated Liver Enzyme Elevations Occurred Without Reported Liver Symptoms
Healthy adults developed elevated liver enzymes during a four-week CBD trial despite not reporting corresponding liver-related symptoms. The finding shows why the absence of symptoms cannot substitute for the laboratory endpoint being studied.
A repeated-dose randomized trial
The trial involved 201 healthy participants overall and compared CBD at 5 mg/kg per day with placebo over 28 days. The daily amount was divided into two doses, and laboratory assessments were performed weekly.
The primary endpoint was elevation of ALT or AST above three times the upper limit of normal. This threshold concerns blood chemistry; it is not itself a diagnosis of liver failure or a direct measurement of permanent tissue damage.
The signal appeared after repeated exposure
The reported per-protocol analysis found qualifying enzyme elevations in eight CBD participants, corresponding to 5.6% in that analysis, and none in the placebo group. Seven participants met withdrawal criteria for potential drug-induced liver injury, identified at days 21 or 28.
Participants did not experience reported clinical symptoms related to liver function during the study, and enzymes returned to normal within one to two weeks after discontinuation. Reversibility does not erase the treatment-associated laboratory signal.
Other null findings did not cancel the liver result
Measured testosterone, inhibin B and thyroid-related hormone comparisons did not show significant treatment differences. Those endocrine findings concern separate outcomes and cannot establish overall absence of CBD effects.
The sample was healthy, dosing lasted four weeks and the analysis was per protocol. Different products, lower doses, longer treatment and patients taking interacting medicines require their own evidence. This study supports a specific repeated-dose hepatic safety concern while avoiding both an unqualified safety claim and an exaggerated claim of inevitable severe liver injury.
Related: Interpreting clinical cannabinoid outcomes.
Primary research
Cannabidiol and Liver Enzyme Level Elevations in Healthy Adults. JAMA Internal Medicine (2025).
