Only patients with loss of smell for more than a year, and whose loss was associated with post‐infectious or unknown causes, were included. Their baseline score was compared to their six‐month score, and an improvement of 10 percent or better was rated as significant; of 19 patients in the experimental group, six showed significant improvement, while only two of 16 control patients improved. In other studies, Patel and her colleagues have found that as much as 50 percent of patients see changes if they pair their training with a steroid sinus rinse.
A 2024 meta-analysis of 36 olfactory training studies cited a “a notable and statistically significant positive impact of olfactory training on the enhancement of all domains of olfactory function.” Individual studies included in the meta-analysis found a range of improvements spanning 11 percent to 68 percent after 12 to 16 weeks, while one paper found that more people benefited with longer training (58 percent vs. 71 percent).
Patel acknowledges that olfactory training isn’t a sure bet, but it appears to be effective for some people—and it’s simple and inexpensive. She’s developed easy-to-follow instructions for people to use on their own. There’s also early evidence that olfactory training may improve depression and cognitive functioning. UK researchers recently looked at 23 studies of people age 55 and older who participated in olfactory training for smell loss, concluding that it was associated with “measurable changes in olfactory function, improved cognitive function, specifically semantic verbal fluency and working memory, reduced depressive symptoms, and protection from cognitive decline.” But they say more studies are needed to draw firmer conclusions.
Kelly credits olfactory therapy with giving her back some capacity to smell. About two years into her recovery, she was in the Austrian Alps when something shifted. She caught the scent of pine trees and sawdust from a nearby logging site. “There was this flutter in my stomach, this sort of quickening of my insides,” she says. “It was like, ‘I’m alive.’”
Each new discovery about olfaction brings scientists closer to understanding how smell connects to the brain—and how this crucial sense might help reveal or even prevent disease. Kelly counts herself among the lucky ones. Her sense of smell isn’t completely back, but it’s there. And for patients like her, regaining smell isn’t just about detecting odors. It’s about returning to the world.
This story originally appeared at Knowable Magazine.