Vitamin D Nasal Spray Treats Loss of Smell in Mice

Coming after a failed clinical trial involving oral vitamin D supplements, the key breakthrough came from understanding that inflammation blocks the nasal tissue’s ability to convert vitamin D into its active form, calcitriol. By spraying calcitriol directly into the nose, researchers therefore bypassed this problem, significantly reducing inflammation and improving olfactory function in the mice.

To mimic inflammation-induced smell loss, the study used mice that had previously been exposed to cigarette smoke. After a month of treatment with intranasal calcitriol, the mice displayed a restored sense of smell and reduced nasal blockage, as confirmed by CT scans. The improvement brought their smell function nearly back to levels seen in young, non-exposed mice.

Few treatments currently exist for smell loss caused by inflammation. Options such as surgery or lab-made antibodies are limited by risks, high costs, or inconsistent results. The vitamin D nasal spray approach thus offers a potentially simpler, safer, and more affordable alternative. The research team believe their discovery could represent a significant step forward for people suffering from smell loss due to inflammation from smoking, COVID-19, or other causes.

To read how research from the University of Bergen in Norway has found that taking the right amount of vitamin D substantially reduces the risk of death, see this news story on our website.