Scientist holding Covid vaccine next to cannabis plant

Researchers Believe CBD Could Kill COVID-19 (Yes, Really)

CBD potently inhibits COVID-19 replication in lung cells.

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As the world continues to be gripped by the pandemic in 2021, the race to successfully prevent and treat severe COVID-19 and its symptoms are the main focus for researchers and scientists. 

Just last month, a group of researchers in the United States made a pretty bold but compelling claim that cannabidiol (CBD), the primary cannabinoid present in varieties of cannabis, and its metabolite, 7-OH-CBD, potently inhibited COVID-19 replication in infected lung cells.

How did the researchers find this out? What does it mean for cannabis and COVID-19?


  • Researchers discovered CBD is a potent antiviral against COVID-19, reinforcing immune response against the virus and helps prevent viral replication
  • CBD may be able to prevent COVID replication via eradicating viral RNA expression in infected host cells
  • CBD may also help activate interferon pathways and prevent inflammatory “cytokine storms”, which can be deadly during later-stage infection 
  • CBD is king of the cannabinoids against COVID-19, other cannabinoids (CBDA, CBDV, etc) showed very little antiviral activity, THC even prevented CBD from doing its job properly!
  • CBD preventing COVID infection? There’s some hope. Out of 82 patients prescribed with CBD, the total incidences of COVID infection among them was 1.2%

How COVID infects patients (and why it’s useful for you to know)

3D render of corona virus
Corona virus 3-D render. Source: WebMD

COVID-19 is a virus capable of infiltrating your body and causing havoc to your respiratory system. The way it does this is a little complex, so we’ll simplify it in order for you to understand CBD’s ability to inhibit replication later in this article.

  • COVID spreads via respiratory droplets expelled when an infected person sneezes, coughs, or speaks, generally when in close proximity with others, but is known to linger in the air as well. 
  • Once the virus enters the body through the nose and mouth, it attaches its tiny spiky body to specific receptors located all throughout your respiratory system. These receptors are called angiotensin-converting enzyme 2 (ACE-2). 
  • Once it tightly latches on to ACE-2, it continues to burrow further and hijacks the healthy cell underneath, taking control of it like a zombie in The Walking Dead. Some of these infected cells can die later on. 
  • The virus will then replicate and spread via its genetic blueprint (RNA) signaling other healthy cells to create its own version of the virus proteins. 
  • As the virus continues to replicate, the immune system begins to react by initiating antiviral responses and producing anti-inflammatory cytokines (interferons, etc). 
  • In extreme cases, the immune system can become hyperactive, releasing too many cytokines in the body, leading to what’s known as a “cytokine storm”. A cytokine storm will attack infected and healthy cells, often causing extreme sickness and, in some cases, death.

The method behind the researcher’s discovery

Since this research effort was preclinical, no human test subjects infected with COVID were used. Instead, the researchers used A549 human lung carcinoma cells expressing ACE-2 receptors. They then pretreated the cells with 0-10μM of CBD for two hours prior to COVID infection and analyzed them 48 hours later to see if the virus had spread or replicated.

The results were staggering. No replication of the virus occurred at all. CBD, therefore, potently and effectively inhibited the spread of COVID-19 in human lung cells.

But how?

CBD targets and destroys viral RNA expression

If you don’t believe CBD is a tough little cannabinoid, think again. The researchers hypothesized that CBD targets host cell processes to prevent viral replication. These processes are necessary for COVID-19 to spread, often causing significant and detrimental changes to the host cell, sometimes leading to cell damage or death. 

To test out this hypothesis, the researchers analyzed CBD using RNA-sequencing for 24 hours. Almost unbelievably, the analysis showed CBD “effectively eradicated” viral RNA expression in host cells, which prevented viral proliferation and infection.

CBD induces interferons while preventing cytokine storms

In the early stages of coronavirus infection, interferons (antiviral and anti-inflammatory proteins) are rapidly produced by your body as soon as a viral RNA threat is noticed (in this case coronavirus). They’re an incredibly important immune response capable of slowing down and preventing viral replication within infected cells. 

However, viruses successfully fight off interferon defenses and suppress signaling pathways. Thankfully, the researchers believe CBD may reduce viral infection in the early stages to the point where the infected host cell is able to activate its own pathway, causing a higher level of defense against the virus.

And the best part? 

CBD is able to prevent overactive inflammatory responses during later-stage infection. This overactivity is known as “cytokine storms”, which cause fatal tissue damage in the lungs. 

In light of this, the authors note:

Collectively, these results suggest that CBD inhibits SARS-CoV-2 infection in part by activating the interferon pathway leading to degradation of viral RNA and subsequent viral-induced changes in host gene expression, including cytokines.

CBD outshined all other cannabinoids

This is where it gets even more interesting.

The researchers acknowledged cannabis isn’t composed of just CBD. There’s a whole arsenal of similar cannabinoids with equally similar chemical structures e.g. cannabidiolic acid (CBDA), cannabidivarin (CBDV), cannabichromene (CBC), and cannabigerol (CBG).

Chart showing only CBD was effective in inhibiting Covid infection
Figure 2. Limited or no inhibition of Covid infection by Cannabinoids other than CBD.

When a user consumes cannabis, they enjoy all these cannabinoids and their benefits at the same time.

So, can you guess what the researchers did? Yes. They tested them out. And what did they find? The structurally similar cannabinoids listed above displayed limited-to-no antiviral capabilities. CBD was the only potent antiviral agent. 

There’s more.

When THC was combined with CBD in equal measures (1:1 ratio), it actually didn’t create a positive synergistic effect. Instead, THC “significantly suppressed” CBD’s efficacy via competitive inhibition. 

Maybe this is the first time isolated CBD extracts will be seen as superior to full-spectrum.

An insight into COVID patients prescribed with CBD

You’re probably thinking a preliminary study isn’t the same as a real-world scenario. You’re only partially right here. The researchers actually looked into COVID-19 patients prescribed with CBD to see incidences of infection were reduced. 

The results are pretty mind-blowing.

Out of the 82 patients prescribed with CBD, the incidence of COVID was only 1.2%, while the incidence among those not prescribed with CBD was 12.2%.

Chart showing CBD usage in patients reduced Covid-19 positivity
Figure 6. High Dose CBD usage in patients is significantly correlated with a reduction in COVID-19 positivity.

Even though the number of patients assessed is small, the results seem to favor CBD as a preventative measure against COVID-19.

Can CBD be used for other future viruses?

While it’s difficult to say whether CBD can be used for other viruses in the future, the researchers are hopeful. 

What we know right now is CBD inhibits the replication of mouse hepatitis virus (MHV), a species of coronavirus known to infect mice almost the same way COVID-19 does in humans. 

According to the researchers, CBD’s ability to combat MHV is promising, raising the possibility for it to be used for future viruses.

Related Study: Can cannabinoids be added to anti-viral therapies to reduce lung inflammation?