We know that for people who lose their sense of smell after Covid there are two different recovery groups. The experience of loss is the same, but the recovery process is very different.
One group - approximately nine out of ten people - will recover quickly and have no further problems. They might be without smell and taste for a couple of weeks but their senses will return just as swiftly as they lost it. Doctors know that people in this group lost their sense of smell because of a blockage due to congestion high in the upper airway. When that congestion clears, smell returns.
People in the second group also lose their sense of smell suddenly but their recovery takes much longer. They may also have trouble with congestion and changes in how they experience smell. Typically, this group might experience some level of recovery over a couple of months after the virus and then start to experience parosmia and possibly phantosmia. It's important to remember parosmia is considered a sign of recovery as these nerves regenerate.
In this group of people, their persistent smell and taste changes are the result of the virus affecting the structure of the olfactory system. The olfactory system has been damaged by the virus and needs to regenerate, as it is designed to do. Nerve regeneration and the healing process take time - sometimes more than a year.
While the vast majority of people with Covid-19 smell loss recovery quickly and move on, we know that some people will take longer. At the moment, there is no way to diagnose which group a patient might belong to, or why. But knowing there are two pathways explains why some people experience sudden 'cures'.
Social media is offering a wide variety of 'hacks' and 'tricks' to help patients recover their sense of smell. However, just like the craft of magic, it's about timing rather than science. These cures happen when people from the quick-recovery group try out lots of ways to recover their sense of smell, and then spontaneously recover anyway. They understandably assume that the tricks are what worked to regain their smell, because that was the only thing that they did differently and smell came back.
Unfortunately, when the second group tries these tricks, they don't work, and this leads to frustration.
We are still gathering information about outcomes for people with Covid-19 smell loss because it is still happening. So we don't exactly know what will come next. Rest assured that everyone in this group is heard, and your help in sharing your experience helps researchers develop a better understanding.