Coronavirus cures: debunked

6 July 2020

Since the start of the Covid-19 pandemic, readers have been asking us whether alleged cures or treatments for the coronavirus are real or not. 

It’s important to note that, currently, there is no approved vaccine for Covid-19. In the UK only one drug, dexamethasone, has been approved for treating the disease, though others, notably remdesivir, are being trialled.   

The advice from the World Health Organisation (WHO) on avoiding infection is still to clean your hands frequently and thoroughly, avoid touching your eyes, nose and mouth, cover your mouth when coughing with a tissue or the bend of an elbow and keep at least one metre distance from others.

Here’s a look at some of the treatments we’ve been asked about by readers.

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Insect repellent

It was reported in April that the Ministry of Defence (MoD) would be using its laboratories to test whether citriodiol—found in insect repellent—could be used to kill the strain of coronavirus that causes Covid-19 (SARS-CoV-2), after being effective in countering the virus that causes SARS (SARS-CoV-1). It was also reported that some troops were being issued with insect repellent containing citriodiol as part of health protection measures. 

The MoD confirmed to Full Fact that this was all true and its tests were ongoing. No results have been published. It also confirmed that MoD personnel are still being provided with citriodiol.

Blowing hot air up your nose with a hairdryer

This has not been recommended by medical professionals and there is no evidence that this would work.

This myth may have been popularised by a Florida politician, Bryant Culpepper, the Okeechobee county commissioner who had to apologise after he claimed that using a blow dryer up the nose cures Covid-19, during an emergency meeting in March. His theory was that a hairdryer would heat the nostrils to a temperature at which the virus is destroyed. 

YouTube videos alleging the hairdryer treatment works have also been found to be false by fact checkers.

UV light

Ultraviolet light was famously suggested as a treatment for Covid-19 by President Donald Trump. However, the WHO warns that UV radiation can “cause skin irritation and damage your eyes” and it should not be used to disinfect hands or other areas of skin.

The National Academies of Sciences, Engineering and Medicine in the USA says that the strongest type of UV, called UVC, probably kills the new coronavirus, but it should only be used on objects and surfaces, not on the body.    


Although copper won’t cure Covid-19, a study has suggested that the virus cannot survive on copper for very long. While SARS-CoV-2 was detectable for up to 24 hours on cardboard and two or three days on plastic and stainless steel, it lasted just four hours on copper.

The Times has reported on calls from experts to coat doorknobs, handrails and shopping trolleys in copper to try and stop the spread of the virus, but The New York Times has reported doubts that copper-infused accessories like face masks will have much impact at reducing transmission. Ingesting too much copper can also make you ill

Vitamin C

There have been reports of doctors in New York prescribing large doses of vitamin C to critically ill coronavirus patients and a clinical trial is underway in Wuhan, China, to determine if there is any benefit to Covid-19 patients being treated with vitamin C, but no results have been published yet. Currently, there isn’t evidence that vitamin C is a successful cure for or can protect against the coronavirus.

The NHS warns that taking very high doses of vitamin C can cause stomach issues.

Vitamin D

Multiple trials around the world are currently studying whether vitamin D can help with prevention or treatment of Covid-19, and the government has confirmed that Public Health England is “carrying out a rapid review of recent evidence relating to vitamin D”.

However, an article published in the British Medical Journal by a number of UK scientists says there is “no strong scientific evidence” that very high intakes of vitamin D will be beneficial for countering Covid-19, and there are health risks linked to excessive vitamin D intake. We’ve written more about vitamin D and coronavirus here.

The NHS suggests taking 10 micrograms of vitamin D a day to keep bones and muscles healthy, as people who have been spending most of the day indoors may not be getting enough vitamin D from sunlight, but says there is “currently not enough evidence” to support reports about vitamin D reducing the risk of coronavirus.

The National Institute for Care Excellence says: “There is no evidence to support taking vitamin D supplements to specifically prevent or treat COVID-19. However, all people should continue to follow UK Government advice on daily vitamin D supplementation to maintain bone and muscle health during the COVID-19 pandemic.”

The British Nutrition Foundation has said that a well-balanced diet is important for supporting the immune system, but added: “It is critical to address that there is no individual nutrient, food or supplement that will boost immunity, or stop us getting highly infectious viruses, like Covid-19.”


Research into the importance of the throat and salivary glands in Covid-19 infection and transmission has argued that several dental mouthwashes “deserve clinical evaluation” into their ability to disrupt the virus. 

The WHO has said there is no evidence that mouthwash will protect you from infection, adding: “Some brands of mouthwash can eliminate certain microbes for a few minutes in the saliva of your mouth. However, this does not mean they protect you from 2019-nCov infection.”


There were reports in May that scientists from the University of Lethbridge in Canada had claimed strong strains of cannabis could help prevent and treat Covid-19.

Fact checkers PolitiFact cast doubt on these claims, warning that it was only a preliminary study that has not been peer reviewed, and no testing has been done on humans. The lead researcher of the study, Igor Kovalchuk, told PolitiFact it was an “overstatement” to suggest cannabis could prevent Covid-19 infection. 

The American Lung Association has warned that even occasional smoking of marijuana could increase the risk of complications with Covid-19.

Trials into whether cannabis could be an effective treatment are still ongoing, but it is too early to draw firm conclusions. 

Drinking alcohol

The WHO has warned that drinking alcohol does not protect against Covid-19 and can be dangerous, as “harmful use” of alcohol increases the risk of health problems. It has also warned: “In no way will consumption of alcohol protect you from COVID-19 or prevent you from being infected by it.”


Both Reuters and news agency AFP have debunked claims that inhaling vapours or steam can kill Covid-19. There is no evidence of this working.

Drinking or gargling warm or salty water

We have written before about claims that salt water or warm water can protect against Covid-19. There is no evidence for either claim. 

The WHO has said that there’s no evidence saline can prevent Covid-19. However, a team at the University of Edinburgh has recently started investigating whether nasal irrigation or gargling with salt water could be effective against Covid-19, so there may be more information on this soon.Gargling with salt water is recommended by the NHS for adults who have a sore throat to relieve symptoms.

There is no evidence that drinking water of any temperature will prevent coronavirus. The WHO has said: “While staying hydrated by drinking water is important for overall health, it does not prevent coronavirus infection.” 

Alpha-Lipoic Acid

Alpha-lipoic acid (ALA) is an antioxidant that naturally occurs in foods including yeast, spinach, broccoli, potatoes and offal like liver or kidney. A study in Wuhan, China, found critically ill Covid-19 patients given ALA fared better than those given a placebo, but due to how few people were in the study (just 17) it concluded there was only a “borderline statistical difference” between the two groups.

Eating alkaline foods or lemons

One suggested cure is eating alkaline foods, such as certain fruit and vegetables

Misinformation surrounding alkaline foods has existed prior to Covid-19 and we have previously debunked claims that an alkaline diet can prevent cancer. These claims centre on the idea that you can change the pH of your body based on what you eat and that having too acidic a body can cause problems. Many claims about the diet have been widely debunked. Some experts also say following the alkaline diet could lead to nutritional deficiencies.

AP has fact checked a Facebook post that suggested eating alkaline foods will raise the body’s pH level to create an environment which is deadly for Covid-19, but said the post was incorrect and cited non-existent research. 

Lemons are also commonly suggested as a cure. The US National Academies of Sciences, Engineering and Medicine says lemon or lemon juice will not kill Covid-19 and has “no effect on coronavirus infections”.


There is no evidence that eating, drinking or washing with vinegar does anything to stop Covid-19.

Dr Grace Farhat, a lecturer in food science and nutrition at Liverpool Hope University, told The Metro: “There are many people on social media who are currently advising washing hands with apple cider vinegar or drinking large quantities of it. It is highly unlikely this will have any benefit whatsoever. In fact, drinking large amounts could cause more harm than good.”

Injecting seawater

Mexican fact checker Animal Politico reported that this ‘cure’ was tried by hundreds of people in Ecuador in a bid to stop Covid-19. This was not authorised by the government, and strongly condemned by physicians. The article quotes a warning from the Pontifical Catholic University of Ecuador warning that seawater could have faecal contamination and other pathogens, and there is a high risk of causing serious infection by injecting it intravenously. 

Injecting bleach

The WHO warns that spraying or introducing bleach or other disinfectants into your body can be dangerous and should not be done under any circumstances. They can be poisonous if ingested and cause irritation and damage to skin and eyes.

As we have written before, RB, the makers of disinfectants Dettol and Lysol, have warned that “under no circumstance should our disinfectant products be administered into the human body (through injection, ingestion or any other route).”

Homemade hand sanitiser

We’ve been asked whether making your own hand sanitiser, or using vinegar or lemon juice as an alternative to hand sanitiser, is effective. 

Soap and water are considered more effective than hand sanitiser. It is not advisable to make your own hand sanitiser. 

Dr Sally Bloomfield, a professor at the London School of Hygiene and Tropical Medicine, told The Guardian that homemade sanitiser could be “dangerous” and hurt your hands without the added emollients in shop-bought products that make them softer on the skin. Daniel Parker, assistant professor of public health and the University of California, told CNN it would be very difficult to ensure the concentrations are correct in homemade sanitiser.

Temperature changes

We’ve been asked about whether hot or cold temperatures will kill the virus. The WHO says there is “no reason to believe” that coldness will prevent the virus, and that you can be infected “no matter how sunny or hot the weather is”.

St John’s Wort 

St John’s Wort is a herbal remedy usually used as a treatment for depression. There is no evidence of it being used to treat or cure Covid-19. It can weaken the effect of life-saving medicines and cause dangerous side effects.

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