The most effective method for restoring a lost sense of smell is olfactory training, a structured daily practice of sniffing specific scents that helps regenerate the nerve pathways between your nose and brain. Most people who lose their smell after a viral infection recover within six months, but active training and a few supplemental strategies can speed the process and improve outcomes for those with lingering loss.
Why Smell Loss Happens
Your sense of smell depends on a thin layer of specialized nerve cells high inside your nasal cavity. When a virus, head injury, or chronic sinus inflammation damages these cells or the nerve signals they send to the brain, smell fades or disappears entirely. The good news is that olfactory neurons are among the few nerve cells in the body that can regenerate throughout your life. That regeneration is what makes recovery possible, but it takes time and often benefits from deliberate stimulation.
Post-viral smell loss is by far the most common type. After COVID-19 specifically, about 74% of people self-report recovery within 30 days, and roughly 96% recover within six months. Recovery can continue for at least two years after infection, with about 11% of people in one study regaining their smell after the six-month mark. Around 5% develop persistent loss that lasts beyond two years.
How Olfactory Training Works
Olfactory training is the closest thing to physical therapy for your nose. You systematically expose your smell receptors to strong, distinct odors, which encourages damaged neurons to regenerate and rebuild their connections. It is the single most recommended intervention across clinical guidelines for smell loss, regardless of the cause.
The standard protocol uses four scents that each represent a different odor category: rose, eucalyptus, lemon, and clove. You sniff each scent individually for 20 to 30 seconds, twice a day, ideally once in the morning before breakfast and once in the evening before bed. The minimum recommended duration is 24 weeks, but longer training produces better results. In patients with post-infectious smell loss, training for a full year yielded significantly better outcomes than stopping at 16 weeks.
You can set this up at home with four small jars (around 50 mL each). Essential oils work well: rose, eucalyptus, lemon, and clove oil on cotton pads inside each jar. Hold each jar about an inch from your nose and inhale gently while concentrating on the scent. Even if you can’t smell anything at first, the exposure still stimulates the nerve cells. Over weeks and months, faint impressions often begin to return, sometimes as distorted versions of the original smell before eventually sharpening.
A meta-analysis of clinical trials confirmed that olfactory training significantly improves smell scores compared to no treatment. Combining training with additional therapies boosted the likelihood of recovery by 65% compared to training alone.
Treatments That Complement Training
Nasal Vitamin A Drops
Vitamin A plays a direct role in regenerating olfactory receptor neurons. In a study of patients with post-infectious smell loss, 37% of those who used intranasal vitamin A drops alongside olfactory training showed clinically meaningful improvement, compared to 23% who did training alone. The protocol involved applying 10,000 IU of vitamin A in drop form daily for eight weeks, with the head tilted back so the liquid reaches the upper nasal cavity. This is worth discussing with a doctor, as the drops need to be compounded by a pharmacy.
Saline Nasal Rinses
Rinsing your nasal passages with saline helps by physically clearing mucus, inflammatory debris, and allergens that can block scent molecules from reaching your smell receptors. Two studies found significant improvement in smell function after just one month of regular saline irrigation. You can use a standard neti pot or squeeze bottle with a premixed saline packet. This is a low-risk addition to daily training that keeps the nasal lining hydrated and functional.
Corticosteroids for Sinus-Related Loss
If your smell loss is tied to chronic sinus inflammation or nasal polyps, the underlying swelling is physically blocking scent molecules from reaching your nerve cells. Clinical guidelines strongly recommend both oral and nasal corticosteroids for smell loss caused by chronic sinusitis. For allergic rhinitis, nasal steroid sprays combined with antihistamines are moderately recommended. These medications reduce swelling in the nasal passages and can produce rapid improvement when inflammation is the primary problem. They are less useful for post-viral nerve damage, where the issue is the neurons themselves rather than a physical blockage.
What to Expect During Recovery
Recovery from smell loss is rarely a straight line. Most people first notice faint, partial smells or “phantom” odors that don’t match what they’re actually sniffing. Foods might taste metallic or chemical before gradually tasting normal again. This distortion, called parosmia, is actually a sign that nerve pathways are reconnecting, even though it can be unpleasant.
In one large follow-up study, 49% of post-COVID patients had fully recovered their smell within about seven weeks, 14% had partial recovery, and 37% still experienced some dysfunction. For those in the slower recovery group, consistent olfactory training over nine months showed clear benefits compared to doing nothing. The key takeaway: if you’re still struggling at three or six months, that does not mean permanent loss. Keep training.
Staying Safe While Your Smell Is Gone
A missing sense of smell creates real safety gaps that are easy to overlook. You can’t detect a gas leak, a smoldering fire, or spoiled food the way you normally would. A few practical adjustments make a significant difference:
- Gas and carbon monoxide detectors: Install natural gas detectors near any gas appliance (stove, boiler, fireplace) and carbon monoxide detectors in every room with a fuel-burning device. Carbon monoxide is both odorless and potentially fatal, making detectors essential.
- Smoke detectors and heat alarms: Test smoke detectors regularly. In the kitchen, a heat alarm (which triggers at temperatures above 57°C rather than in response to cooking fumes) prevents false alarms while still catching real fires.
- Cooking timers: Set a timer every time you put something on the stove or in the oven. Without smell, you lose your early warning system for burning food.
- Food safety by dates, not sniffing: Follow use-by dates strictly and label foods with the date you opened them. The “sniff test” is no longer available to you, so when in doubt, throw it out.
- Appliance upgrades: If you have a gas stove, consider models with flame-failure devices that automatically shut off gas when no flame is detected. Switching to electric appliances eliminates the gas leak risk entirely.
When Loss Has a Treatable Cause
Before committing to months of training, it’s worth confirming why your smell disappeared. Nasal polyps, chronic sinusitis, severe allergies, and certain medications can all reduce or eliminate smell, and treating the underlying cause can bring rapid improvement that no amount of sniff training would achieve on its own. A simple nasal endoscopy can reveal structural blockages, and imaging can identify sinus disease. If your smell loss came on gradually rather than suddenly after an infection, a treatable physical cause is more likely.
For post-viral loss, the combination of daily olfactory training, saline rinses, and possibly nasal vitamin A drops represents the best current approach. Start the training as soon as possible after losing your smell. Earlier intervention is associated with better outcomes, and the protocol costs almost nothing to maintain at home.