What you need to know
Cannabidiol (CBD) is a cannabis compound with some medicinal properties. Unlike tetrahydrocannabinol (THC) — the main psychoactive component of cannabis — CBD does not produce a high or euphoria. The U.S. Food and Drug Administration (FDA) has approved one CBD-based medication to treat seizure disorders; other medications are in the development and testing pipeline.
Now some early studies show that CBD could help block infection with SARS-CoV-2, the virus that causes COVID-19.
What did the researchers do?
In a series of studies supported by the National Institute of General Medical Sciences, the National Institute of Allergy and Infectious Diseases, the National Cancer Institute (NCI), and the National Center for Advancing Translational Sciences, researchers tested the effects of CBD and other cannabis compounds on SARS-CoV-2. They looked at interactions between CBD and the virus in human lung cells and in mice. They also analyzed data from the National COVID Cohort Collaborative’s health records of volunteers who had been prescribed the CBD-based medication to help prevent seizures.
What did they learn?
In both the laboratory studies and the health records analyses, CBD seemed to have a protective effect against SARS-CoV-2. When the virus was introduced to human lung cells treated with CBD, it could not replicate and take hold as it usually does. Mice that were given therapeutic doses of CBD before being exposed to the virus were much less likely to develop COVID-19 than mice in the control group. And human patients who took the CBD-based medication were less likely to report a COVID-19 diagnosis than others, including people who had the same seizure disorders but had not been prescribed that medication.
Interestingly, out of more than 100 compounds in cannabis, only CBD showed this protective effect. In fact, when CBD was combined with THC, its ability to protect decreased.
What does this mean?
More research, including clinical trials, is needed, but these studies suggest that CBD might be a useful way of preventing COVID-19 in the future. The researchers caution that CBD is not a replacement for vaccination, masking, and social distancing. If anything, they write, CBD would be used along with these measures to prevent breakthrough infections.
The researchers also emphasize that the CBD used in their studies is different from the nonmedical products consumers might be familiar with. There is no evidence that taking over-the-counter CBD products can prevent or treat COVID-19 infection.
Where can I go to learn more?
NCI provides patient-friendly information about cannabis and its compounds.
The National Center for Complementary and Integrative Health has more information about cannabis and CBD.
N3C is a partnership among several NIH Institutes and Centers that aims to use COVID-19 clinical data to answer critical research questions.
Nguyen, L. C., Yang, D., Nicolaescu, V., Best, T. J., Gula, H., Saxena, D., Gabbard, J. D., Chen, S., Ohtsuki, T., Friesen, J. B., Drayman, N., Mohamed, A., Dann, C., Silva, D., Robinson-Mailman, L., Valdespino, A., Stock, L., Suárez, E., Jones, K. A. … Rosner, M. R. (2022). Cannabidiol inhibits SARS-CoV-2 replication through induction of the host ER stress and innate immune responses. Science Advances, 8, eabi6110. https://www.science.org/doi/10.1126/sciadv.abi6110
NIH COVID-19 Resources by Topic
COVID-19 research information and resources by topic from NIH institutes and centers