Intended for healthcare professionals


Sixty seconds on . . . smell training

BMJ 2021; 373 doi: (Published 26 April 2021) Cite this as: BMJ 2021;373:n1080

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  1. Abi Rimmer
  1. The BMJ

What’s that?

Essentially, it’s actively sniffing the same four scents every day for several months.1 The idea is that it can help you to recover your sense of smell if you’ve lost it for two weeks or more.

Why are we talking about it?

As you know, loss of smell, or olfactory dysfunction, is a common symptom of covid-19. Research has found that 60% of patients experience loss of smell within the first four days of covid-19 symptom onset, however for most people this improves over time.2

What if it doesn’t improve?

That’s where smell training comes in. A group of international researchers have said that smell training should be used instead of systemic corticosteroids because it has no known side effects, is low cost, and is supported by a robust evidence base.3

Is it common to use corticosteroids?

Yes. As one of the report’s authors, Carl Phillpott, explains, “Corticosteroids are a class of drug that lowers inflammation in the body, and they have been considered as a therapeutic option for smell loss caused by covid-19. But they have well known potential side effects including fluid retention, high blood pressure, and problems with mood swings and behaviour.”

Did smell training exist before the pandemic?

It did, although the researchers say that covid-19 has caused an unprecedented demand for smell training. “We estimate that with over 4.4m covid-19 infections in the UK, there will be over 260,000 people with persistent smell loss or distortion. This means we have seen a great increase in demand for both information and treatment,” Phillpott said.

What should I smell?

According to the smell loss charity Fifth Sense, studies suggest you should choose scents that represent the four smell categories: flowery, fruity, spicy, and resinous. They say, however, that you can choose any smell you feel comfortable with, have available, and enjoy.4

Does it require special equipment?

No, Fifth Sense says you can use things that you already have at home such as ground coffee, a pepper grinder, or a sprig of fresh herbs. Smell these for around 10 seconds each at least twice a day, ideally in the morning and evening. Delicious!