January 4, 2023 – Personalized essential oils may help people regain their sense of smell lost as a consequence of COVID-19, in keeping with a brand new study.
The process is known as olfactory training and involves usually smelling the oils to “challenge” the nerves liable for sending olfactory messages to the brain. The Mayo ClinicThese nerves are known to have the ability to heal and regrow in a process called neuroplasticity.
The study was published last week in JAMA Otorhinolaryngology. It included 275 people aged 18 to 71 who had lost their sense of smell as a consequence of COVID-19. Participants smelled the oils for 15 seconds, pausing for 30 seconds between smells. The study lasted 3 months.
A conventional smell training protocol uses 4 specific scents: rose, lemon, eucalyptus and clove. One group in the brand new study used these scents, while one other group smelled 4 scents they selected themselves from 24 scent options. A 3rd control group didn't take part in the smell training. In addition, a subset of study participants were shown pictures of the scents they smelled.
Although there have been no “definitive” differences between the approaches, the researchers found that allowing patients to each select their scents and see pictures of the scents could be useful.
In a companion comment Carol Yan, MD, of the University of California, San Diego, who published the study alongside the trial, said the improvements some patients noted can have been a placebo effect and must be considered in treatment plans for patients who've lost their sense of smell as a consequence of COVID-19.
“Allowing patients to select their own odorants may improve cost-effectiveness and increase treatment adherence, particularly when there is a problem with familiarity with one of the classic 4 odorants,” she wrote. “Adding visual cues to [olfactory training] may improve engagement in some patients but increase distress in others. Ultimately, patients' belief and satisfaction with their treatment plan may have significant placebo effects that cannot be ignored.”
An estimated 700,000 people have lost their sense of smell as a consequence of COVID-19, the authors said. Most people regain their sense of smell inside a 12 months.