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As the COVID-19 pandemic entered its second year, researchers continued to investigate potential therapeutics for the prevention and treatment of the respiratory disease. One such possibility was cannabidiol (CBD), a non-psychoactive chemical compound found in cannabis plants. Two studies published in January 2022 showed promise for the use of CBD and two related hemp compounds when it came to infection by SARS-CoV-2, the virus that causes COVID-19. The findings were featured in a number of publications and on social media, including the meme below, sent to our team by Snopes readers: It’s true that one study found that two cannabinoids, CBDA and CDGA, may prevent some coronavirus variants from entering human cells, while a second concluded that CBD may prevent the virus from replicating and further worsening infection. However, there are several caveats worth noting before rushing to the local dispensary. We explore those — and each individual study — below. Hemp and marijuana are both derived from cannabis plants, scientific name Cannabis sativa, the main difference between them being the amount of the psychoactive chemical tetrahydrocannabinol (THC) they contain. Hemp is a fiber made from marijuana plants that contains no psychoactive components and can be used as a source for a variety of things, from food supplements to cosmetics. With a THC content of less than .3%, consuming hemp will not create a high. Cannabidiol, or CBD, is a chemical compound found in all cannabis plants — both marijuana and hemp — typically made from oil found in the plant’s stalks, leaves, and flowers. In the U.S., the only CBD drug product approved by the Food and Drug Administration is Epidiolex, which is used in the treatment of seizures. To be federally legal for consumer use, CBD products must be derived from hemp and contain no more than .3% THC. Understanding how SARS-CoV-2 infects humans is a key component to combating the virus. Ongoing research since the onset of the pandemic has described the multistep entry process, in particular the spike protein that is known to bind to a human protein known as ACE2 receptor, or angiotensin-converting enzyme 2, to infect humans. ACE2 is found on the surface of many cell types in the human body, which allows for plenty of targets for coronavirus to strike. Known collectively as cell entry inhibitors, that’s why so many drugs, vaccines and antibody therapies have targeted the spike protein. Once infected, the virus replicates itself to hijack the body, so to speak. Each of the studies we analyzed looked at these two key components of viral infection and how CBD or hemp may influence either the virus’ ability to infect cells or replicate once it has successfully invaded. To understand how hemp may prevent SARS-CoV-2 from entering human cells, researchers at Oregon State University used a chemical screening technique known as affinity selection-mass spectrometry (AS-MS) to show how to prevent SARS-CoV-2 from entering human cells (but not actual humans). AS-MS allows certain compounds known as botanical ligands, in this case hemp, to bind to selected targets, such as a spike protein. Publishing their work in the peer-reviewed Journal of Natural Products, the team showed that two compounds found in hemp, cannabigerolic acid (CBGA) and cannabidiolic acid (CBDA), could successfully bind to the spike protein and prevent it from binding to ACE2 in human cells, impairing the virus’ ability to infect. Both CBGA and CBDA were equally effective against the alpha and beta coronavirus variants. (The compounds were also effective against a pseudovirus that expresses a spike protein similar to the one found in SARS-CoV-2.) These compounds can be taken orally and have a long history of safe use in humans, said study author Richard van Breemen in a news release. They have the potential to prevent as well as treat infection by SARS-CoV-2. CBDA and CBGA are produced by the hemp plant as precursors to CBD and CBG, which are familiar to many consumers. However, they are different from the acids and are not contained in hemp products. Together, the findings show the potential to possibly treat and prevent infection, but the researchers caution that the use of CBDA and CBGA could be used as a compliment, not a substitution, for preventative measures like antiviral treatments and vaccination. A second study published in the peer-reviewed journal Science Advances also concluded that CBD can inhibit the infection of SARS-CoV-2 in human cells and in mice — though again, not in humans. This time around, scientists at the University of Chicago treated human lung cells with a dose of CBD for two hours before exposing the cells to SARS-CoV-2 and monitoring for infection. While the treatment was not shown to prevent infection, it was shown to inhibit the virus’ ability to replicate within six hours of cells being infected. The CBD also had the same effect in two other types of cells, and three variants of SARS-CoV-2. Additionally, the team found that mice who were treated with CBD for one week before infection were also shown to suppress infection in the lungs and nasal passages, further suggesting that the CBD may slow replication of the virus. CBD has anti-inflammatory effects, so we thought that maybe it would stop the second phase of COVID infection involving the immune system, the so-called ‘cytokine storm.’ Surprisingly, it directly inhibited viral replication in lung cells, said study author Marsha Rosner in a news release. Finally, the team also analyzed the records of 1,212 patients from the National COVID Cohort Collaborative, a collection of clinical data related to COVID-19 in patients in the U.S. They found that those taking a medically prescribed oral solution of CBD for epilepsy tested positive for COVID-19 at lower rates than those who were not, which shows an association but not causation. While CBD may offer a potential preventative and treatment for COVID-19, the researchers of both studies concluded that the future clinical trials and research are required to determine whether CBD could actually treat or prevent COVID-19, particularly as neither analyzed CBD in actual humans but only in human cells, animals, and as part of a database analysis. Furthermore, neither study investigated potential risks associated with taking CBD and how consumption may impact certain populations, such as pregnant people. It should also be noted that the CBD used in the studies was produced in high purity, specially formulated doses in specific situations and not commercially available CBD products, many of which are made with additives. In short, it’s too early to tell whether CBD will help against COVID-19. That is an answer that further research hopes to find. In the meantime, CBD consumption is not to be used as a replacement for known protective measures like vaccination and existing public health guidelines.
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