If you've lost your sense of smell due to a virus, there may soon be a way of getting it back – temporarily, at least. Scientists from Britain's University of East Anglia, along with colleagues from the Smell & Taste clinic at the James Paget University Hospital, have found that use of a sodium citrate nasal spray gets some people smelling again.

In cases where viruses or other non-obstructive causes lead to a loss of smell, the researchers suspected that calcium molecules in the nose may be part of the problem, as calcium is believed to be capable of "turning down" the sense of smell. That's where the sodium citrate comes in.

Already medically-approved as a treatment for stomach and bladder issues, the salt is also known to bind calcium. It was hoped that when applied as a nasal spray, it could "mop up" calcium molecules in the nasal mucus, thus temporarily restoring the sense of smell.

In a randomized trial, 55 test subjects who had lost their sense of smell were treated with a spray of either sodium citrate or sterile water – they didn't know which. They were then asked to sniff increasingly stronger concentrations of four odors (roses, pear, vinegar and menthol), letting the researchers know at which concentration they could actually smell them.

While the sterile water made no real difference, approximately one third of the people treated with the sodium citrate showed a marked improvement. The peak effect kicked in 15 to 30 minutes after the treatment, and lasted for up to two hours. Side effects were minor, and included sore throat, a runny nose and itching.

"Further study in the form of larger clinical trials with patients applying the treatment regularly would help inform whether this treatment should be offered routinely by doctors," says East Anglia's Carl Philpott, who is leading the project. "It could quite easily and safely be formulated into a treatment to provide temporary relief from smell loss, enhancing the quality of life of patients with very few side effects."

A paper on the research was recently published in the journal Clinical Otolaryngology.