Smell training (also known as olfactory training) is a safe, evidence-based treatment for patients with a reduced sense of smell (hyposmia or anosmia) or an altered sense of smell (parosmia). More information about smell loss can be found here.
There are many causes of smell loss, and the outlook for an individual's sense of smell can be difficult to predict. Smell training can therefore be effective in some patients and not in others. However it can produce some improvement in a significant proportion of patients, even if recovery is not 100%.
Further information on smell training can be found at abscent.org.
How does smell training work?
Smell training is very straightforward to perform. The first step is to gather a collection of four familiar scented items, oils or perfumes. The process involves sniffing each of the four scents for about 20 seconds at a time, whilst concentrating on the smell. This should be performed at least once a day.
Smell training is thought to work by taking advantage of neuroplasticity - the capacity of the brain to "re-wire" itself to compensate for injury, as well as stimulating the remaining olfactory nerve endings to survive.
Who may benefit from smell training?
Smell training may lead to improvement in any person with smell loss, regardless of the underlying cause. However, it is likely that its effects are greater in those with post-viral smell loss, compared to people with smell loss caused by a head injury.
People with partial smell loss (hyposmia) of recent onset, and people with parosmia (distortion of the sense of smell), are more likely to benefit that people with long-standing complete smell loss.