To be clear, CBD cannot cure COVID or prevent you from catching it, however ground-breaking research is showing that CBD could be an extremely useful tool in fighting this infection. This would be a great advantage in countries with limited access to medical care and vaccines. CBD has the potential to act as an antiviral agent at early stages of infection and protect against an over-active immune system at later stages of infection.
Researchers at several labs around the world have independently found that CBD can assist with the fight against COVID in two ways (1,2,3,4,5,). It has been found that CBD inhibits the binding of the virus to a lung cell surface receptor called ACE2 (Angiotensin-converting enzyme). Secondly because CBD down-regulates the production of cytokines (chemicals produced by the body’s immune system to fight infection, but also the cause of inflammatory conditions such as arthritis) it has potential to treat the “cytokine storm” that causes the severe respiratory distress and often death in severely ill COVID patients.
Cell Surface Binding, Protecting the Lung “Gateway” Against Infection:
SARS-CoV-2 virus enters the host lung cell by binding to a surface receptor (Angiotensin-converting enzyme 2, ACE2) using a spike protein on the virus. The lungs are the gateway of infection for COVID. On entering the cell, the viral genome is translated into two large polypeptides, which are severed by viral proteases (MPro and PLPro) to produce the proteins for viral replication, assembly and budding. To test the effect of CBD, researchers pre-treated human lung carcinoma cells which express ACE2 with 10uM CBD for 2 hours before infecting them with SARS-CoV-2. The cells were evaluated 48 hours later, and it was found that CBD inhibited viral replication. The CBD was found to trigger significant changes in cellular gene expression, in particular expression of transcription factors. Changes in the host cells induced by the virus were reversed.
Suppression of the “Cytokine Storm”
Another significant finding is that CBD suppressed the triggering of the hyperinflammatory response known as the “cytokine storm” which is the causes of death resulting from a COVID infection. CBD was found to normalise levels of apelin, a peptide known to reduce inflammation, decrease physical lung damage associated with adult respiratory distress syndrome (ARDS), and improve oxygen levels (6,7). CBD has been shown to inhibit synthesis of inflammatory cytokines including IL (interleukin) 2, IL6, IL1α and β, gamma interferon, inducible protein 10, monocyte chemoattractant protein-1, macrophage inflammatory protein-1α and tumour necrosis factor α (6) in mice where lung injury was induced. In mice with induced chronic asthma, CBD reduced cytokine synthesis, airway inflammation and fibrosis (8).
Numbers of research teams have undertaken laboratory trials and a range of cannabinoids have been tested and only CBD has been found to significantly aid COVID-19 infected cells.
The hope is that further research will be funded to take these impressive early results into animal and human trials. Unlike many anti-viral drugs, CBD is well tolerated in animals and humans in doses up to 1500 mg per day for periods of 2 weeks (9,10). Clearly there is a way to go, methods of delivery, dosages, and at what point in infection should be CBD be taken have to be considered. For example, taking CBD could offer some level of protection against catching COVID, but taking it in early stages of infection could be damaging to the immune system because of the down regulation of cytokine synthesis. If you are severely ill and in respiratory distress, CBD might be another useful way to help relieve the symptoms. The public health message is clear however, wear a mask, wash your hands, and practice social distancing. If you are considering trying CBD always consult your health care professional.
- Raj et al. Int. J. Biol. Macrobiol. 168 (2021) 474-485
- Wang et al. Nature Preprints (2020) 2020040315(doi:1020944/preprints202004.0315.v1)
- N. Byrareddy and M. Mohan.Brain Behav. Immun. 87 (2020) 120-121
- Esposito et al. Br.J. Pharmacol. 21 (2020) 4967-4970
- Scheau et al. J. Pers. Med. (2021) May 31,11 (6):494.doi.10.3390/jpm11060494
- H et al. Cannabis Cannabinoid Res. 5 (2020) 197-201
- Salles E. et al. J. Cellular and Mol. Med. (2020)
- Ribeiro et al. Immunopharmacol.Immunotoxicol 37 (2015) 35-41
- Vuolo et al. Eur. J. Pharmacol. 843 (2019) 251-259
- J. and Kaplan B. Cannabis Cannabinoid Res. 5 (2020) 12-31