Essential Oils: Effect Against Corona And Cold Unclear
Essential oils smell good and are very versatile. Do they also protect against infections with viruses? Studies with humans have so far been lacking.
No question, eucalyptus or lemon balm oil provides fresh air and a pleasant smell at home. But the oils should not only be appealing but also healthy: sprayed or evaporated in the room, essential oils should purify the air of viruses. At least that is reported by various media.
And: Inhaling with essential oils is said to protect against colds and flu. Just sniffing the fragrant oil is supposed to put viruses away, a well-known manufacturer claims.
Some now want to use the essential oils against the coronavirus.
We received a request from a reader who wanted to know what was wrong with these claims. As part of a comprehensive research, we looked for scientific answers: Does it prevent spraying, inhaling, rubbing against the skin or dripping into the bath water?
Do they protect against infections with the new coronavirus and other respiratory infections?
Essential Oils Effect Against Corona- Studies with people are missing
People have never investigated whether essential oils are suitable as room fragrances or inhalation for the prevention or treatment of colds or flu. Neither is it known whether it helps to bathe in essential oils, rub them on the skin or smell them.
Also speculative is the claim that essential oils can protect against infections with the new corona virus. Studies on this are missing.
Capsules for colds with no effect?
A small study has investigated whether essential oils are effective against colds when swallowed as capsules. Patients who sought medical help for cold complaints took part in the study. They swallowed capsules of thyme, oregano, and sage essential oils for a week. In the meantime, they reported on their complaints.
There was no difference between those who swallowed the oils and those who took a dummy medication (placebo). The cold lasted about the same length in both groups and the symptoms were similar.
If the study were solid, this result would suggest that the essential oils are no better than a placebo. However, the study has so many shortcomings that it is not meaningful.
In addition, we could not find any studies that examined the effects of essential oils directly on humans.
The mix of partly unknown substances
Essential oils are a mixture of many chemical ingredients. Plants form these oils to attract insects, but also to protect themselves from pathogens and pests. Little is known about which of the ingredients work and which mechanisms are behind them.
That is why scientists in the laboratory are testing the effects of these substances against various pathogens. The goal: to recreate the ingredients in order to use them in the manufacture of medicines. Indeed, certain essential oils have a promising effect against viruses, bacteria and fungi. They could be a possible alternative to previous medications, for example, antibiotics.
Effect in the laboratory …
In the laboratory, for example, it was observed how cineol, a common ingredient in essential oils, strengthens the immune system’s response and thus fights influenza viruses. However, this experiment did not take place in humans, but in the noses of mice.
In the test tube, the essential oil of lemon balm also appears to inhibit the spread of flu viruses. Various essential oils have successfully fought herpes viruses in laboratory tests, i.e. the cause of cold sores.
The laurel essential oil even showed activity against SARS-CoV, a close relative of the new coronavirus. However, only in the test tube.
… does not mean effect in humans
And that’s why it’s important not to jump to conclusions. Viruses behave differently in the laboratory than in the body. A test tube is not a good model for the human organism with its complex metabolism. What is missing in the test tube, among other things: the immune system, human metabolism and many chemical substances that play a role in the body.
A virus in a test tube is exposed to the active ingredients of essential oils without protection. In the human body, however, the virus penetrates the body cells in order to multiply there. In the case of the new corona virus, for example, these could be the cells of the lungs. Once in the cell, the virus for the active ingredients of the essential oils may no longer be accessible.
Hope air purification
On the Internet, both aromatherapy fans and manufacturers often refer to the results of a study  carried out in an Italian hospital. An evaporator distributed a mixture of essential oils (lavender, cajeput, myrtle and geranium) in the air in a waiting room.
According to the research team, fewer bacteria and fungi were subsequently found on the furniture than in another waiting room. The research team concluded from this observation that the evaporation of oils has a disinfectant effect on the indoor air. In this study, however, only bacteria and fungi were examined, but not viruses.
Cold viruses and the corona virus migrate from one person to another in tiny droplets when talking, coughing or sneezing. It is questionable whether indoor air treated with essential oils can prevent them from doing so.
Of course, but not without danger
Despite the lack of scientific data, the pleasantly scented oils are popular. This may also be due to the fact that the image of the natural is attached to them.
But be careful: “Natural” does not automatically mean “harmless”. The use of essential oils, especially in concentrated form, can be risky.
This is especially true for children. Allergic reactions, severe skin irritation or drug interactions are possible. When swallowed, some oils can be toxic even in small quantities.
The studies in detail
We looked for studies on the effects of essential oils. Do they affect the risk of infection and the duration of viral respiratory infections? In our research, we were only able to find a study that did not take place in the laboratory.
With spices against viruses?
It took place in 2015 on the Greek island of Crete. The research team wanted to know whether essential oils from a variety of thyme, oregano or sage (Origanum dictamnus, Salvia fruticosa and Thymus vulgaris) can shorten the duration of colds.
A total of 105 people took part in the study, who sought medical help with typical cold symptoms. The participants were randomly assigned to one of two groups.
One group swallowed a capsule with essential oils twice a day. The other group received a dummy treatment (placebo). Neither the participants nor the study team knew who belonged to which group. Blood tests and throat swabs were also performed at the beginning and end.
For a week, the participants provided information about their complaints by telephone every day. On a scale of 0 to 7, they should indicate how stressful their symptoms were.
The result: After a week, there was no difference between the groups, whether they swallowed essential oils or a dummy treatment.
Maybe no cold at all?
The study has some shortcomings: for example, only 45 of the 105 participants were apparently actually infected with a virus – this is the result of the throat swabs. However, these are far too few people for a meaningful result.
The remaining participants could have suffered from bacterial infections or allergies, some suffered from severe chronic respiratory diseases. That could also have distorted the result.