Nearly 77% of coronavirus patients experienced some degree of smell loss as a result of their infections, a recent study found.* Though the number of new COVID-19 cases are dropping across much of the United States, increasing numbers of patients and survivors are either experiencing: parosmia (i.e., a disorder that causes previously normal or enjoyable scents to suddenly smell foul) or anosmia, which is losing their senses of smell altogether. 

Fortunately, several studies have indicated that “smell training” can help people who have lost their senses of smell to various viral illnesses. Based on this evidence, researchers and medical professionals are recommending smell training to patients suffering from smell dysfunction as a result of COVID-19 infection.

What exactly is smell training?

Smell training, also called scent training, involves sniffing several potent scents twice a day to stimulate, improve, and hopefully restore, your sense of smell. Many individuals regain their sense of smell within a couple of weeks to a couple of months after losing it, but many don’t.

If your sense of smell hasn’t started to come back after a couple of weeks, then you may want to start scent training. Be prepared for your smelling ability to return in stages. If you’ve lost that sense completely, any scents you do smell may at first seem unpleasant. 

Before you begin your training, make sure that some other health condition isn’t causing the disorder. “I saw somebody recently who had smell dysfunction following COVID-19,” said Dr. Sunthosh K. Sivam, an ear, nose and throat specialist in Houston, “and it turned out they had inflammatory nasal polyps.” Once the polyps were removed, the dysfunction healed.

What scents should I use?

Experts recommend choosing four strong, distinct, familiar scents that evoke strong and vivid memories. You can use soap, shampoo, cologne, food, spices, flowers, or other handy items. 

Some people have had success using unpleasant smells such as sour milk or rotten eggs.

You can also buy a special ‘scent kit’ that contains essential oils, or purchase individual oils of your choice, either online or at your local natural products store. Rose, lemon, eucalyptus, and clove are standard scents for this purpose.

What does smell training actually involve?

While there’s no authoritative method for conducting scent training, experts offer similar suggestions: 

• Keep your scents in an easily accessible location. 
• Smell each scent for about 20 seconds (so the entire session lasts about one minute).
• Take short sniffs rather than deep inhalations.

Additionally, Dr. Nicholas R. Rowan, an assistant professor of otolaryngology-head and neck surgery at the Johns Hopkins University School of Medicine in Baltimore, suggests looking at a picture of what you’re smelling as you’re sniffing it, such as a picture of a lemon while sniffing a lemon scent, as it helps your brain make yet another connection.

How long should I continue the training?

Generally, doctors advise their patients to do smell training twice a day for three months.

“Keep on training for a year if you have to,” said Dr. Thomas Hummel, a researcher at the Smell and Taste Clinic of the otorhinolaryngology department at the Technical University of Dresden in Germany, whose work has informed the odor training methods now used around the world.

Many factors can affect your training success, including your age. Younger people tend to recover their sense of smell after a viral infection more easily. This is partly because most people lose olfactory receptor neurons as we age, and recovery is slower in general.

How can I stay motivated?

Just as when you’re trying to lose weight or learn a new skill, it’s easy to get frustrated with any training program that doesn’t immediately yield your desired results, but it’s important to hang in there. Dr. Rowan suggested the following tips:

• Record each training session on a calendar to help make the training a habit.
• Keep a diary of your experiences from each session.
• Join an online community of peers for support and encouragement.

An England-based non-profit called AbScent, which focuses on smell disorders, also offers an app called Snif that can help you track your progress. “You have to keep up with it,“ cautioned Chrissi Kelly, AbScent’s founder. “It’s not a quick fix.” 

“It’s very frustrating for patients,” Dr. Rowan admitted. “They seek out this care because they can’t smell and want it fixed and then we say, ‘Hey, use this sensory function that you don’t have.’” To his knowledge, however, “this is the best thing out there.”

*Caron, C. (2021, Mar. 26). Covid Stole Your Sense of Smell? Try Physical Therapy for Your Nose. The New York Times. https://www.nytimes.com/2021/03/26/well/live/covid-anosmia-smell-training.html 

Much about the novel coronavirus, i.e., COVID-19, is still not fully understood. As research progresses and our knowledge of the virus increases, information can change rapidly. We strive to update all of our articles as quickly as possible, but there may occasionally be some lag between scientific developments and our revisions.