More than a third of individuals diagnosed with COVID-19 report a temporary loss of taste or smell, according to recent research. So it’s no surprise that many people are looking for unique ways to both cope with and safely regain their olfactory abilities.
That’s why the decade-old concept of smell therapy is quickly regaining interest as a possible treatment for smell loss from COVID-19, a common (but usually temporary) symptom of the virus. Also known as olfactory retraining or smell training, some research suggests it could represent an affordable, convenient way to retrain your olfactory system. But questions remain about how effective it might really be—especially when it comes to COVID-related smell loss.
What is smell therapy?
The first thing to know is that smell therapy is not new—some of the first evidence that it might be helpful emerged in a 2009 preliminary study in Laryngoscope, Tran Bao Locke, M.D., assistant professor of otolaryngology at Baylor College of Medicine, tells SELF. In this study, 40 patients experiencing a loss of smell exposed themselves twice a day to four scents: rose, eucalyptus, lemon, and cloves. After 12 weeks, the participants who used this therapy did better on odor identification tests than 16 control participants who didn’t get the therapy.
Future studies have used basically the same protocol for olfactory therapy: Patients purchase essential oils or fragrance sticks in four specific scents. Then they will deeply inhale each scent for 15 to 20 seconds, usually twice a day. “Just as there are three primary colors of red, blue, and yellow, there are four primary smells,” Raj Sindwani, M.D., an otolaryngologist at Cleveland Clinic, tells SELF. They are floral (rose), fruity (lemon), aromatic (cloves or lavender), and resinous (eucalyptus).
But smell therapy isn’t just about the simple act of sniffing fragrances—patients also need to focus on what the scent represents while smelling it. Essentially, the idea is that this retrains both your brain and nose to recognize those smells. “It’s important that you understand that, for example, this is a rose smell you’re supposed to be smelling,” Dr. Sindwani explains. “The idea is for you to try and think about what roses smell like and what they look like by combining visual imagery with the stimulation of the isolated scent.”
Even with consistent smell therapy, it may take a few months to a year for someone to have significant improvement in their sense of smell, Dr. Sindwani says.
How does smell therapy work?
The exact biological mechanism by which smell therapy helps patients improve this sense isn’t totally understood right now, Dr. Locke says. But there are some theories.
You process smell via your olfactory system, which starts with olfactory receptors “up high in the sinuses,” Dr. Locke says. Normally, airborne odor particles activate these receptors, which then send signals to the brain’s olfactory bulbs (two collections of nerve cells on the underside of the brain) through the olfactory nerves. From there, that smell information gets processed by many areas in the brain, including the amygdala and hippocampus (which are involved in memory and emotional processing) as well as parts of the cortex.
Experts think that viral illnesses, such as COVID-19, can damage the olfactory receptors in the sinuses, Dr. Locke explains, and those illnesses may even damage the cells in the olfactory bulb. “But if you have any sort of smell at all, it means that the olfactory nerve is working and is probably in the process of trying to repair itself,” she says. There is even research to suggest that regaining a sense of smell involves neuroplasticity—the formation of new neurons and neuronal connections—in the olfactory processing system.
The goal of smell therapy, then, is “to stimulate your sense of smell and assist with your recovery,” Dr. Locke continues. By using physical and psychological elements to reteach the olfactory system, Dr. Sindwani says, patients can use “memory and experience to train those nerves to come back to life.”
Should you try smell therapy for COVID-related smell loss?
Though smell therapy has been around for more than a decade, researchers are looking at it with renewed interest due to the fact that loss of smell is so common after COVID-19, Dr. Sindwani says. But the loss of smell after COVID-19 is typically temporary. Although it may take weeks or months, that sense of smell usually comes back on its own. In that case, is olfactory therapy still worth a shot?
Most people will regain their sense of smell within a few weeks after COVID-19, Dr. Locke says, but it might not be exactly the way you remember it. “It may not be 100% or it may be altered from what it was previously,” she explains. So if you’re experiencing a prolonged loss of smell or you’re finding that your sense of smell isn’t up to snuff, smell therapy might be a simple way to speed the healing process up.
Smell therapy for COVID-related smell loss is a relatively new area of study because the coronavirus has only been around for a little over a year, Dr. Locke says. But there is some promising research that suggests it’s worth a shot. For instance, a 2020 review study in the International Forum of Allergy and Rhinology, researchers looked at 36 past studies about smell therapy for virus-related loss of smell (but not COVID-19 specifically). The authors concluded that smell therapy could be helpful for this kind of smell loss, especially because it’s relatively cheap, safe, and convenient.
And, for a small preliminary study published in January 2021 in the European Archives of Oto-Rhino-Laryngology, researchers looked at 27 people who had persistent smell loss at least five weeks after COVID-19 (but were not hospitalized during their illness). Of those participants, 9 were given 10 days of oral corticosteroids along with olfactory training and 18 participants received olfactory training only. Although some patients in the smell-training-only group did experience improvements in their sense of smell 10 weeks later, only those who received smell training with the corticosteroids saw a statistically significant improvement.
This study suggests that smell training can help some patients who are dealing with prolonged loss of smell after COVID-19, especially when paired with corticosteroid medications. But the study is quite small, and there is some controversy about the use of corticosteroids in COVID-19 patients. As research into this area continues, we’ll get a better sense of how much smell therapy on its own can help people dealing with this issue.
In practice, Dr. Locke and Dr. Sindwani both say they’ve had success in treating patients with smell loss from COVID-19 through smell therapy alone. As long as patients don’t have other possible reasons for their lack of smell (such as nasal polyps or head trauma), they continue to recommend that people give it a try.
“It’s a very simple kind of approach,” Dr. Sindwani says. “There are no side effects and it’s patient-driven, which are all great things that you would want in therapy.”
If you’re having COVID-related smell issues, this therapy might help.
Though smell loss from COVID-19 is often temporary, if that’s something you’re experiencing, Dr. Locke says it might be worth it to be proactive and consult with your doctor or an otolaryngologist to see if smell training would be a good option for you. Insurance generally doesn’t cover smell therapy, but the necessary oils tend to be relatively affordable (in the $10 to $30 range).
There are other treatment options for prolonged COVID-related loss of smell, such as intranasal medications and corticosteroids. They can even be used alongside smell training to help patients. But because smell training has so few potential risks and is generally cost-effective, experts say it’s worth considering for people who are dealing with smell loss after having the coronavirus.
“Smell training has been around for a while, is very safe to do, and it doesn’t hurt to try,” Dr. Locke explains. “I think patients will be surprised with that kind of progress.”
Related:
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