Covid and Licorice

Covid and Licorice

As we progress through the fall and into winter, I will continue to offer natural solutions to coping with COVID-19, adding to the existing material already stored in the archives of these newsletters. Today we will examine a detailed study on the subject of licorice and its value for this condition.

Realizing that “safe and efficient drugs to combat the current COVID-19 pandemic are urgently needed”, these progressive scientists “analyzed the anti-coronavirus potential of the natural product glycyrrhizic acid (GLR)”, which they believed could both fight the virus infection as well as treat the respiratory symptoms associated with COVID.

Glycyrrhizic acid (GLR), also known as glycyrrhizin, “is a triterpenoid saponin mainly isolated from the roots of the plant Glycyrrhiza glabra” ( European licorice).

Before embarking on this research, the scientists worked on finding a worthy substance, seeking a “drug” (while not a drug per se, GLR is an isolated extract of licorice), “that could not only inhibit viral replication but also interfere with the entry of the virus into cells”.

Previous research led them to consider licorice a viable candidate.

GLR as a Medicine

GLR has been used for over 40 years in Japan to treat liver diseases, especially chronic hepatitis, and, due to its remarkable anti-inflammatory properties, atopic dermatitis, along with other inflammatory skin diseases.

Due to the safety and affordability of licorice extracts, the clinical use of GLR has been increasing. As a result, according to the researchers, there have been “clinical trials to investigate the benefit of GLR in multiple pathologies such as depression (Cao et al., 2020), Parkinson’s disease (Petramfar, Hajari, Yousefi, Azadi, & Hamedi, 2020) and different cancers, such as hepatocellular carcinoma and pancreatic cancer (Kwon et al., 2020)”.

GLR has proven effective against some animal viruses, and has been tested in AIDS patients (at a dose of 400–1600 mg/day, given intravenously), where “the viral antigen was no longer detected at the end of the treatment course, suggesting a marked inhibition of HIV-1 replication”.

Then, the research material they were looking at became more germane to the subject at hand.

First off, licorice extracts have been used for centuries in Chinese medicine (in formulas) for treating upper respiratory infections.

Furthermore, in 2002, a Japanese clinical study done on military patients, being treated for upper respiratory tract infections, found “that GLR therapy was associated with a shorter hospitalization, lower-grade fever and lower cost of therapy compared with controls”.

Then, “in 2003, it was reported that GLR effectively inhibited the replication of two clinical isolates of SARS-associated coronavirus (FFM-1 and FFM-2) in Vero cells”.

After combing through all the scientific literature on the use of GLR, and licorice extracts, they concluded that “GLR should be rapidly tested as an anti-SARS-CoV-2 agent, alone and in combination with other drugs (notably CQ/HCQ and tenofovir) to combat the current COVID-19 pandemic”.

They also pointed out in their conclusion that, “While this manuscript was reviewed, three groups also proposed the use of GLR, alone or in combination with other drugs, to treat coronavirus infections. Notably, one study underlined the capacity of GLR to bind to the angiotensin converting enzyme 2 (ACE2) which represents a SARS-CoV-2 receptor. Therefore, the targeting of ACE2 could be very useful to inhibit the virus from diffusing out of infected cells and to enter new cells. Even more recently, a study reported interesting clinical data for a patient with severe COVID-19 who recovered upon treatment with diammonium glycyrrhizinate. These data are encouraging and support our proposal to clinically evaluate GLR as a drug to treat SARS-CoV-2 infections, considering notably that the drug and derivatives have shown activity against other SARS-coronavirus.”

To check out this overview study, and all their references to the other studies mentioned, follow this link: Study


The conclusion of this study does point out that “the risk of hypertension induced by GLR, due to pseudo-hyperaldosteronism, should not be neglected.” And indeed, prolonged heavy intake of licorice has been linked to high blood pressure, and in a few cases to adrenal malfunction, heart issues, and lowered testosterone (in men). Thus, licorice products and extracts should be avoided by those with hypertension, and should be used judiciously by the rest. (For more detailed information see this article, “Licorice abuse: time to send a warning message”, which, while extreme, does offer all potential dangers of too much licorice.)


Now, there is a form of licorice lozenge used to treat acid reflux, called deglycyrrhizinated licorice (DGL). DGL has the majority of the glycyrrhizin removed, so that it can be used three times a day (or more), without any negative effects on blood pressure.

However, the astute reader will have noticed that glycyrrhizin is the other name for GLR, and therefore DGL will be of no value in preventing COVID or other viral conditions.

Oral Licorice

Aside from the fact that DGL lozenges will not work for virus prevention, the ideal of licorice lozenges, or pure licorice extract candies, turns out to be a good idea.

This study, published Sept 9, 2020, confirms that “glycyrrhizin (GZ) is a promising agent against SARS-CoV-2 as its antiviral activity against SARS-CoV has already been confirmed. It is worthwhile to extrapolate from its proven therapeutic effects as there is a high similarity in the structure and genome of SARS-CoV and SARS-CoV-2. There are many possible mechanisms through which GZ acts against viruses: increasing nitrous oxide production in macrophages, affecting transcription factors and cellular signalling pathways, directly altering the viral lipid-bilayer membrane, and binding to the ACE2 receptor”.

But, here is where they take a different tack: “In this review, we discuss the possible use of GZ in the COVID-19 setting, where topical administration appears to be promising, with the nasal and oral cavity notably being the potent location in terms of viral load. The most recently published papers on the distribution of ACE2 in the human body and documented binding of GZ to this receptor, as well as its antiviral activity, suggest that GZ can be used as a therapeutic for COVID-19 and as a preventive agent against SARS-CoV-2.”  (Study)


For those of us with healthy, stable blood pressure, it might be a good idea to incorporate licorice tea, and/or the aforementioned licorice extract candies (the ones made from pure licorice), on a semi-regular basis. Licorice capsules are also available, though it does appear that having licorice run through the oral passages may be of the most value. And it will probably not be long before we see a nasal spray with a licorice base, if others are paying attention to this research.

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