Losing your sense of smell during or after COVID-19 can be more than an inconvenience. For some people, smell returns within days or weeks. For others, the problem can persist for months or longer, sometimes causing a complete loss of smell, reduced ability to detect odors, or changes in the way familiar smells are perceived.
Medical terms help describe these different smell disorders. Anosmia means a complete or near-complete loss of the sense of smell. Hyposmia means a reduced ability to smell. Other disorders, including parosmia, can cause familiar smells to become distorted or unpleasant.
Post-COVID smell loss is one type of olfactory dysfunction, but COVID-19 is not the only possible cause. Persistent smell problems can also occur after other viral infections, nasal and sinus disease, head trauma, certain medications, aging, and neurological conditions.
When smell loss persists, an evaluation by an otolaryngologist can help determine what is causing the problem and whether treatment may be appropriate.
What Is Post-COVID Loss of Smell?
Post-COVID loss of smell refers to persistent or recurrent impairment of the sense of smell following a COVID-19 infection.
The severity can vary considerably. Some people cannot detect odors at all, while others can smell only strong scents. Some patients notice that food seems bland or that they have difficulty identifying specific flavors. Others experience a change in smell quality rather than simply losing sensitivity.
These symptoms fall under the broader category of smell and taste disorders, although smell and taste are separate senses.
COVID-19-associated olfactory dysfunction may include:
- Anosmia: complete loss of smell
- Hyposmia: reduced ability to smell
- Parosmia: distorted or altered perception of smells
- Phantosmia: smelling an odor that is not actually present
- Reduced ability to appreciate flavor
- Changes in the perception of food and beverages
The distinction matters because treatment and prognosis can depend on the type and cause of the disorder.
Why Does COVID Cause Loss of Smell?
Smell begins when odor molecules reach specialized sensory tissue high inside the nasal cavity. Olfactory receptor cells detect these molecules and transmit information through the olfactory pathway to the brain, where odors are identified and interpreted.
COVID-19 can interfere with this system.
Research suggests that SARS-CoV-2 can affect cells that support the olfactory sensory system and may trigger inflammation and disruption of normal olfactory function. In some people, the system recovers relatively quickly. In others, recovery is incomplete or abnormal.
Persistent post-COVID olfactory dysfunction may therefore involve more than simple nasal congestion.
This is one reason that a person can continue to have significant smell loss even when the infection itself has resolved and the nose feels relatively normal.
Anosmia vs. Hyposmia: What Is the Difference?
The terms anosmia and hyposmia are sometimes used interchangeably in everyday conversation, but they describe different degrees of smell dysfunction.
Anosmia is the absence or near absence of the ability to smell.
Hyposmia is a reduction in the ability to detect odors. A person with hyposmia may still recognize strong smells but have difficulty detecting subtle aromas.
For example, someone with hyposmia may smell coffee when standing close to a cup but have difficulty detecting its aroma from across a room.
A formal smell evaluation can help quantify olfactory function rather than relying solely on a patient’s subjective impression.
Why Does Food Taste Different After COVID?
Patients frequently describe post-COVID smell loss as a loss of taste.
The distinction between taste and flavor is important.
The tongue detects basic taste qualities such as sweet, salty, sour, bitter, and umami. Much of what people experience as the flavor of food, however, depends on the sense of smell.
When olfactory function is reduced, food can seem bland even though the taste receptors on the tongue are still functioning.
This is why someone with post-COVID anosmia or hyposmia may say:
“I can taste that something is sweet, but I can’t taste what I’m eating.”
Persistent changes in the ability to smell or appreciate flavor should be evaluated as a potential smell disorder rather than automatically assumed to be a problem with the tongue or taste buds.
What Is Parosmia After COVID?
Not everyone with post-COVID olfactory dysfunction experiences complete smell loss.
Some people develop parosmia, a condition in which normal odors smell different from how they smelled before.
Coffee, onions, meat, perfume, toothpaste, or other familiar substances may suddenly smell unpleasant, burnt, chemical-like, metallic, or otherwise abnormal.
Parosmia can occur during the recovery phase of an olfactory disorder. Although it can be frustrating, a change in smell perception does not necessarily mean that recovery is impossible.
Because smell disorders can take different forms, an appropriate evaluation should distinguish anosmia, hyposmia, parosmia, and other olfactory symptoms.
How Long Does Loss of Smell Last After COVID?
There is no single recovery timeline.
Many people recover their sense of smell relatively quickly, while others experience persistent dysfunction. Recovery can be gradual, with subtle changes occurring over an extended period.
A lack of complete recovery does not necessarily mean that no improvement is possible. However, persistent symptoms deserve medical evaluation, particularly when they interfere with eating, quality of life, safety, or the ability to recognize environmental odors.
The longer smell dysfunction persists, the more important it becomes to establish whether COVID-19 is actually the cause.
When Should You See an ENT for Post-COVID Smell Loss?
Consider an evaluation if:
- Your sense of smell has not returned after COVID-19.
- You can smell only very strong odors.
- Food continues to seem unusually bland.
- Familiar smells have become distorted.
- You experience phantom smells.
- Your symptoms are getting worse rather than better.
- You have chronic nasal congestion, sinus symptoms, or other nasal problems.
- You experienced a head injury before the smell loss began.
- The smell disorder is significantly affecting your quality of life.
An ENT evaluation is particularly important because not every case of persistent anosmia or hyposmia is caused by COVID-19.
How Is Anosmia or Hyposmia Diagnosed?
A comprehensive evaluation begins with a detailed medical history.
An otolaryngologist may ask:
- When did the smell problem begin?
- Did it occur during or after COVID-19?
- Was there nasal congestion or a sinus infection?
- Has smell function improved, worsened, or remained unchanged?
- Can you detect strong odors?
- Do foods taste different?
- Are smells distorted?
- Do you experience phantom odors?
- Have you had previous nasal surgery or head trauma?
- Are you taking medications that could affect smell?
The physical examination may include an examination of the nose and nasal passages. Depending on the symptoms and findings, nasal endoscopy, formal smell testing, CT imaging, MRI, or other testing may be appropriate.
The purpose is not simply to confirm that smell is reduced. It is to determine why.
Treating Post-COVID Loss of Smell
Treatment depends on the cause, duration, severity, and type of olfactory dysfunction.
There is no single treatment that works for every patient.
Potential approaches may include:
Olfactory Training
Olfactory training, sometimes called smell therapy, involves repeated exposure to selected odors as part of a structured program designed to stimulate the olfactory system.
Recent systematic reviews and meta-analyses have found evidence that olfactory training can improve objective smell function and quality of life in people with COVID-related olfactory dysfunction, although protocols vary and additional research is needed to establish the ideal approach for every patient.
Olfactory training may be recommended alone or as part of a broader treatment plan.
Treating Nasal or Sinus Disease
If inflammation, chronic rhinosinusitis, nasal polyps, allergies, or another condition is contributing to smell loss, treatment may focus on the underlying nasal or sinus disorder.
This is one reason a complete ENT evaluation is important before assuming that persistent smell loss is exclusively neurological or post-viral.
PRP Treatment for Loss of Smell
Platelet-rich plasma, or PRP, is an emerging treatment being studied for persistent olfactory dysfunction.
PRP is prepared from a patient’s own blood. A small blood sample is processed to concentrate platelets and associated growth factors. The resulting platelet-rich preparation can then be administered as a targeted treatment.
For selected patients with persistent nerve-related smell loss, PRP may be considered as part of an individualized treatment plan.
Research is encouraging but still developing. A 2025 systematic review and meta-analysis of randomized controlled trials found that PRP was associated with improvements in objective and subjective olfactory scores and a higher response rate in patients with COVID-related olfactory dysfunction. However, only four randomized trials involving 198 participants met the inclusion criteria, so larger and better-standardized studies are needed.
For that reason, PRP should be described as a promising treatment option rather than a guaranteed cure for anosmia or hyposmia.
What Does PRP Treatment for Smell Loss Involve?
At NY Otolaryngology Group, patients being considered for PRP undergo an initial evaluation to determine whether the treatment is appropriate.
The evaluation described by the practice includes a patient questionnaire, nasal and sinus examination, nasal endoscopy, and smell testing. Depending on the individual case, CT or MRI imaging may also be recommended.
For appropriate candidates, the nasal passages are anesthetized before PRP is administered near the olfactory fibers.
The practice’s current protocol involves two PRP treatments approximately one month apart, followed by a three-month follow-up to assess the response. The practice also recommends structured smell therapy following treatment.
Treatment plans can vary depending on the patient’s diagnosis and clinical circumstances.
Can PRP Treat Anosmia and Hyposmia?
PRP is being investigated primarily as a treatment for olfactory dysfunction, including persistent smell loss following COVID-19.
Because anosmia represents severe loss of olfactory function while hyposmia represents partial loss, both conditions may fall within the broader category of olfactory disorders evaluated for treatment.
However, candidacy for PRP should not be determined by the diagnosis alone.
The underlying cause matters.
A patient whose smell loss is caused by nasal obstruction, chronic sinus disease, medication effects, neurological disease, or another treatable condition may require a different approach.
The goal of an evaluation is therefore to identify the cause of the smell disorder and determine whether PRP or another treatment makes sense.
Is PRP a Treatment for Taste Loss?
Patients often search for PRP treatment for loss of smell and taste because smell and flavor are closely connected.
However, it is important to distinguish the two senses.
PRP research in this area has primarily focused on olfactory function, meaning the ability to detect and identify smells. If a person’s reduced enjoyment of food is primarily caused by loss of smell, improvement in olfactory function may change the way food tastes or, more accurately, how flavor is perceived.
That does not mean PRP should be represented as a proven treatment for every type of taste disorder.
A proper evaluation should determine whether the patient’s problem is primarily olfactory, gustatory, or a combination of both.
Is There Hope for Persistent Post-COVID Smell Loss?
Yes, but expectations should remain realistic.
Some patients experience spontaneous recovery. Others benefit from structured olfactory rehabilitation. Emerging treatments such as PRP are being investigated for people whose smell function remains impaired despite time and conservative treatment.
The current evidence does not support a single universal treatment for every patient with post-COVID anosmia or hyposmia.
Instead, the most appropriate approach is individualized:
- Identify the type of smell disorder.
- Look for an underlying nasal, sinus, neurological, traumatic, medication-related, or post-viral cause.
- Measure olfactory function when appropriate.
- Treat reversible causes.
- Consider olfactory training.
- Discuss emerging treatments such as PRP when clinically appropriate.
- Monitor the patient’s response over time.
Living Safely With Loss of Smell
Smell also serves an important safety function.
People with significant anosmia may not detect smoke, natural gas, spoiled food, or other potentially dangerous odors.
If your sense of smell is substantially reduced, consider using functioning smoke and carbon-monoxide detectors and taking additional precautions when checking food freshness or detecting household hazards.
When to Seek Evaluation for Anosmia or Hyposmia
Persistent loss of smell should not simply be dismissed as something that has to be lived with.
Whether your symptoms began after COVID-19, another viral infection, a sinus condition, or an injury, an ENT evaluation can help determine the underlying cause and identify appropriate treatment options.
For patients with persistent anosmia, hyposmia, parosmia, or other smell and taste disorders, evaluation may also determine whether therapies such as olfactory training or PRP are appropriate.
Schedule an Evaluation for Persistent Loss of Smell
If you continue to experience anosmia, hyposmia, parosmia, or other smell and taste disorders after COVID-19, an evaluation with an experienced otolaryngologist can help determine what may be contributing to your symptoms.
NY Otolaryngology Group evaluates patients with persistent smell disorders and can discuss appropriate treatment options, including olfactory training and, for selected patients, PRP therapy for loss of smell.
Contact the office to schedule an evaluation and determine which approach is appropriate for your individual condition.
Frequently Asked Questions
Post-COVID loss of smell refers to the persistent or recurrent impairment of the sense of smell following a COVID-19 infection. It can range from complete loss (anosmia) to reduced ability to smell (hyposmia), distorted smells (parosmia), or phantom smells (phantosmia). This condition can affect the perception of flavors and make food seem bland or unpleasant.
COVID-19 can affect the olfactory system by targeting cells that support the sensory neurons responsible for smell, causing inflammation and disruption of normal function. This interference can lead to anosmia or other smell disorders, and symptoms may persist even after the infection resolves and nasal congestion subsides.
Anosmia is the complete or near-complete loss of the ability to smell, while hyposmia is a reduced ability to detect odors. People with hyposmia may still recognize strong smells but have difficulty detecting subtle aromas. These distinctions are important for diagnosis and treatment.
Food may taste different after COVID-19 because much of what we perceive as flavor depends on the sense of smell. While the tongue detects basic tastes like sweet or salty, reduced olfactory function can make food seem bland or alter flavor perception, even if taste buds are unaffected.
Parosmia is a condition where familiar smells become distorted or unpleasant, such as coffee or onions smelling burnt or chemical-like. It can occur during recovery from post-COVID olfactory dysfunction and indicates changes in smell perception rather than complete loss.
The duration of smell loss after COVID-19 varies widely. Some people recover within days or weeks, while others experience persistent dysfunction for months or longer. Recovery can be gradual, and persistent symptoms should be medically evaluated to determine the cause and appropriate treatment.
You should see an ENT specialist if your sense of smell has not returned after COVID-19, if you can only detect very strong odors, if food tastes bland, if familiar smells are distorted, if you experience phantom smells, or if symptoms worsen. An evaluation is important to identify the cause and explore treatment options.
Diagnosis involves a detailed medical history and physical examination by an otolaryngologist. The evaluation may include nasal endoscopy, formal smell testing, and imaging studies like CT or MRI to determine the cause of smell loss and guide treatment.
