FDA Study Finds High Doses of Consumer CBD May Increase Liver Enzymes

Recent research by the U.S. Food and Drug Administration (FDA) has indicated that consuming high doses of cannabidiol (CBD), particularly around 400 mg daily, might lead to elevations in liver enzyme levels in healthy adults. CBD, a nonpsychoactive component of cannabis, has gained popularity among consumers since the 2018 Agricultural Improvement Act legalized hemp, leading to a surge in unregulated CBD products.

Currently, only one CBD-based medication, Epidiolex, has FDA approval for treating specific seizure disorders, with recommended doses reaching up to 25 mg/kg daily — that’s about 2,000 mg per day for an 80 kg adult. At these higher doses, previous studies have documented a dose-dependent risk of liver enzyme elevation, which can indicate liver stress or damage.

However, safety data on lower doses, such as 200 to 400 mg daily, have been inconsistent. To better understand this, researchers conducted a randomized, double-blind, placebo-controlled trial published in JAMA Internal Medicine. The study investigated the effects of four weeks of twice-daily CBD use at a dose of approximately 5 mg/kg (roughly 253-550 mg daily depending on body weight) in 201 healthy adults.

Participants were assigned to receive either CBD or a placebo for 28 days. Blood tests measured liver enzymes and hormone levels at various points. The results revealed that 8 out of 151 CBD users (about 5.6%) experienced significant elevations in liver enzymes—over three times the normal upper limit—suggesting possible drug-induced liver injury. No such elevations were observed in the placebo group.

Interestingly, these enzyme elevations occurred after three weeks of use, peaked within one or two days of stopping CBD, and returned to normal within a week or two. Some participants also showed increased eosinophilia, a marker often associated with allergic responses, leading researchers to suggest further investigation into the long-term safety of CBD, especially at doses commonly consumed without medical supervision.

While these enzyme increases did not cause severe liver dysfunction during the study, the findings highlight the importance of cautious use, regular monitoring, and further research. The study emphasizes that even lower doses of CBD, taken over short periods, can impact liver health, calling for increased awareness and regulatory oversight in the growing CBD market.

Source: https://medicalxpress.com/news/2025-07-fda-links-high-consumer-cbd.html