A lost or reduced sense of smell is usually not serious. The NHS and HSE say the most common causes are a cold, flu or COVID-19, sinusitis, hay fever, or nasal polyps. The HSE adds smoking. It often gets better in a few weeks or months.
It is also common to lose some sense of smell as you get older. Less often, it is linked to medicines or to brain conditions such as Parkinson's disease.
See a GP if your sense of smell has not come back after a few weeks. A GP can check your nose for causes such as sinusitis or polyps, and refer you if needed.
Get help now
Loss of smell on its own is rarely an emergency. But:
Call 112 or 999 in Ireland, 999 in the UK or 911 in the US if, after a head injury, someone:
Call for an ambulance if someone has a seizure for the first time.
Get an urgent GP appointment if:
See a GP if:
The NHS and HSE describe four kinds:
Both say a change in smell can be unpleasant and can affect how things taste.
More common than people think. A 2021 review pooled studies of 175,073 adults from the general population. On average they were 63.5 years old. It found some smell loss in 22.2%. The rate was higher when smell was tested (28.8%) than when people were asked (9.5%). It was also higher in studies of people over 55.
So many people have some smell loss without noticing it.
The NHS lists a loss of taste and smell among common cold symptoms. Both the NHS and HSE list a loss or change in smell or taste as a COVID-19 symptom. The HSE says this could mean they have gone completely or are just different to normal.
For some people, the change lasts. The NHS lists changes to smell or taste among long COVID symptoms. We look at the research on long COVID and the brain separately.
The NHS and HSE list a reduced sense of smell as a symptom of sinusitis. Other symptoms include pain or tenderness around the cheeks, eyes or forehead, a blocked nose, green or yellow mucus and a high temperature. The HSE says sinusitis is common after a cold or flu.
The HSE says a GP may refer you to an ear, nose and throat (ENT) specialist. This is if medicines do not help, or sinusitis lasts more than 3 months.
The NHS lists loss of smell among hay fever symptoms.
The NHS describes nasal polyps as painless soft growths inside the nose. Symptoms include a blocked or runny nose, mucus dripping down the back of the throat, a reduced sense of smell or taste, and snoring.
The NHS says polyps can feel like a cold. The difference is that colds clear up within a few days, while polyps do not get better unless treated. A GP can usually spot them by looking inside your nose.
The HSE lists smoking as one of the most common causes. Read about what quitting smoking gives back.
The NHS and HSE both say it is common to lose some of your sense of smell with age.
Medicines. The NHS says some medicines can cause smell changes. Check the leaflet, and talk to your pharmacist or GP. Do not stop a prescribed medicine on your own.
Parkinson's disease. The NHS lists loss of smell as a Parkinson's symptom that "sometimes occurs several years before other symptoms develop". On its own, loss of smell is far more often caused by something in the nose. See our guide to Parkinson's disease.
Dementia with Lewy bodies. A 2019 study followed 1,280 people with REM sleep behaviour disorder, where people act out their dreams. Those with a poor sense of smell were more likely to go on to develop Parkinson's, dementia with Lewy bodies or a related condition. Read about REM sleep behaviour disorder and why Lewy body dementia gets missed.
Epilepsy. The NHS lists "strange smells" among the unusual sensations a seizure can cause. Brief phantom smells that come with other odd sensations or loss of awareness are worth raising with a GP.
Head injury. If smell changes after a head injury, get it checked. See the box above for emergency signs. Our concussion guide covers recovery.
The NHS says a GP will check for obvious causes, such as sinusitis or nasal polyps. They may refer you to a specialist for tests if they are not sure what the problem is.
It helps to tell your GP:
The NHS and HSE say your sense of smell may come back by itself in a few weeks or months. Treating the cause might help. For example, steroid nasal sprays or drops may help sinusitis or nasal polyps.
For polyps, the NHS says surgery may be suggested if there is no improvement after about 12 weeks. It says polyps often grow back within a few years.
Both say that sometimes changes in smell cannot be treated and may be permanent.
The NHS and HSE say smell training can help some people. It usually involves sniffing a set of strong scents, such as rose or lemon, regularly over several months.
A 2026 review pooled 10 randomised trials in 628 people with smell loss after COVID-19. Smell training improved scores on smell tests and quality of life compared with control groups. The effect on smell scores was small. The authors advised caution, because training methods varied between studies.
If an infection or allergy is affecting your smell, the NHS and HSE say rinsing your nose with salt water may help. Both give a home recipe: a pint of boiled water left to cool, with a teaspoon of salt and a teaspoon of bicarbonate of soda. Make a fresh batch each day. Sachets are also sold in pharmacies. Salt water washes are not suitable for children.
The HSE warns that you may not be able to smell gas leaks, smoke or fire, or spoiled food. It suggests you:
The NHS and HSE say it may return in a few weeks or months. See a GP if it has not come back after a few weeks. Sometimes the change is permanent.
It can be an early sign of Parkinson's, but that is uncommon. The NHS and HSE say colds, COVID-19, sinusitis, allergies and polyps are far more common causes. Mention it to a GP if it comes with tremor, stiffness, slowness or acting out dreams.
This is called parosmia: things smelling different from how they should. The NHS lists changes to smell or taste among long COVID symptoms. Smell training may help some people.
Yes. The NHS and HSE list sinusitis, allergies and nasal polyps among the most common causes. Treating the cause, for example with a steroid nasal spray, may help.
This article is general information, not medical advice. It cannot diagnose the cause of your symptoms. Talk to your GP or pharmacist about your own symptoms, and before starting, stopping or changing any medicine.
Reviewed by: Proco Team
Last updated: November 2026