Why Your Sense of Smell Can Worsen With Age and What to Do About It

Oftentimes, just the thought of a pleasant aroma (think: freshly cut grass, your morning cup of coffee or just-baked apple pie) can trick your brain into conjuring up its scent.

But as you age, your once-keen sense of smell may take, well, a nosedive.

It's true: As you grow older — especially once you reach the age of 70 — your sense of smell can weaken, according to the National Library of Medicine (NLM).

In fact, "half of people over 65 have some decreased sense of smell," says Philip Chen, MD, FARS, an associate professor of otolaryngology and rhinology at the University of Texas Health Science Center at San Antonio.

Depending on the cause, this decline in smell perception — known as "hyposmia" when it's a partial loss and "anosmia" when it's a complete loss — may be temporary or permanent, per the Mayo Clinic.

Here, discover what causes older adults to lose their sense of smell, and learn what you can do to regain your sniffing ability.

Most of us take our sense of smell for granted, but the capacity to perceive different scents is important for so many aspects of life and health.

For one, smell perception is intimately connected to your sense of taste. If your sense of smell diminishes, food may begin to taste bland and become less enjoyable, according to the National Institute on Aging (NIA).

And if this happens, it may deter you from eating, which can possibly cause malnutrition, unhealthy weight loss and even depression, per the Mayo Clinic.

Not only can a weakened sense of smell affect your overall health and quality of life, but it could even put you in danger. Without a keen sense of smell, you won't be able to detect potentially harmful odors like smoke, gas leaks, spoiled food and other hazardous chemicals, according to the NIA.

While there are many possible reasons for a loss of smell, Dr. Chen says the causes often fall into two broad categories (whether you're an older adult or not):

• ‌Conductive:‌ where smell particles can't get up to the olfactory area at the top of the nose (think: severe nasal blockages like a bad cold or infection, nasal polyps or even tumors)
• ‌Sensorineural:‌ where the olfactory nerves aren't working correctly and the smell fibers aren't picking up or processing the signal properly (think: neurodegenerative disorders, medications and certain viruses, like the one that causes COVID-19)

To break that down further, here are the common causes behind losing your sense of smell:

"With age, we experience a loss of olfactory nerve fibers," i.e., the nerves in your nose, Dr. Chen says.

No one really knows why this happens, but "some believe that the neuroepithelium (where olfactory sensory fibers are located) degenerates with age, much like other nerves in the body," he says. "This degeneration leads to a decreased number of olfactory sensory nerves and causes the olfactory bulb to atrophy."

And with fewer nerves in this nasal area, "we don't perceive smell as well or as strongly," Dr. Chen says.

As you age, your body makes less mucus, which can affect your sense of smell.

The mucous membranes in your nose contain olfactory receptor cells, which play an important role in your ability to smell, according to the Cleveland Clinic.

Before your body can perceive a smell, it enters the nasal cavity and must be absorbed into the mucus of the olfactory lining, Dr. Chen says. "This mucus transmits the smell to your smell receptors," he adds.

Basically, mucus helps keep aromas in your nose long enough for your nerve endings to perceive them, per the NLM.

If you have less mucus, "the ability to carry the smell to the proper location decreases," and with it, your overall sense of smell lessens, too, Dr. Chen says.

But why does mucus production decrease with age, in particular? "We don't have all the answers yet," Dr. Chen says. "One theory is that mucous membranes that line the nose get thinner over time, decreasing mucus-producing cells' productivity."

This thinning may be due in part to poor blood circulation within the mucous membranes, which can cause less humidification of the air you breathe and lead to dryness, he adds.

As we get older, we're more likely to take medicine for a medical condition. Turns out, certain types of medication could be worsening your sense of smell.

"Hundreds of medications have been reported to result in smell loss or changes," Dr. Chen says. "The reasons for these changes depend on the specific pathways and effects the medications have on the body."

"For instance, some antidepressants accumulate in the cell, leading to changes in the biochemical properties of the cell and the response to a stimulus like odorants," Dr. Chen says.

Other common medications that may minimize your sense of smell include antibiotics and blood pressure medicine, according to the NIA.

While cancer treatments can be lifesaving, they can sometimes come with side effects like loss of smell.

For instance, "radiation, especially to the head and neck region, damages the delicate nasal lining," Dr. Chen says.

As a result, your nose makes less mucus, which, as we know, can impair smell.

Similarly, chemotherapy can kill olfactory cells. This is because chemotherapy targets rapidly replicating cells (including olfactory cells) and can't tell the difference between cancerous and healthy, noncancerous cells, Dr. Chen says.

Growing older comes with an increased risk of developing a serious medical disorder, some of which can affect your ability to smell.

For example, neurodegenerative diseases such as Parkinson's, Alzheimer's and dementia are associated with a loss of smell, Dr. Chen says.

In these instances, nerves that connect to the part of the brain that perceives smell — or the brain itself — can deteriorate, thus decreasing one's sense of smell, according to the Mayo Clinic.

Indeed, "some think that inflammation at the olfactory bulb, where smell nerve fibers connect to the brain, causes the nerves to not work as well," Dr. Chen says.

Unfortunately, losing your sense of smell is often out of your control. But there are some things you can do in certain cases to stimulate your sniffer. These include:

"Olfactory training is a safe and simple way to try and bring back smell," Dr. Chen says. "This consists of sniffing four different scents (like rose, clove, eucalyptus and lemon) over months to train the brain how to smell again."

Specifically, you sniff each odor twice a day (before breakfast and at bedtime) for 20 to 30 seconds each, according to StatPearls, while focusing on what the scent used to smell like. For the best results, try sticking to this practice for at least 24 weeks.

While the exact mechanism is unknown, people with olfactory dysfunction due to a prior infection, injury and Parkinson's all seem to benefit from olfactory training.

In fact, patients with post-infectious olfactory problems experienced an improvement in smell after just 16 weeks of olfactory training and reaped even greater outcomes after one year, per a June 2016 study in ‌Rhinology‌‌.‌

Dehydration can lead to dry mouth, per the Cleveland Clinic, and having dry mucous membranes can alter your sense of taste and smell.

To stay well-hydrated (and keep your mucous membranes moist), aim to drink about half your body weight in ounces of water each day. So for example, if you weigh 160 pounds, aim to drink 80 ounces, or about 10 cups of water. (Just make sure to check in with your doctor first, especially if you have kidney, liver or heart issues, or if you're taking medication that causes you to retain water.)

"Many think that loss of smell is due to inflammation of the olfactory nerves and bulb, and as a result, topical steroids are often tried to decrease this inflammation," Dr. Chen says.

For this reason, steroids are often administered in the form of a sinus irrigation or wash to get the medicine high up in the nose, where the olfactory fibers live.

Besides topical treatments, "some doctors try oral steroids, but there's not great evidence this works," he adds.

Certain supplements with known anti-inflammatory properties are also worth trying when regaining your sense of smell.

For example, "you can try fish oil [which contains omega-3s] or vitamin A to help with inflammation," Dr. Chen says.

Talk to your doctor if you notice your nose isn't working like it used to. While the cause is often harmless and a natural part of aging, doctors can help properly assess and determine the root of your smell perception problem.

Once they've found the cause, treatment can be tailored to your specific situation, in the form of olfactory training or medication.

Keep in mind, however, that "if the loss of smell is associated with a new nasal blockage, bleeding, facial numbness, vision changes or lumps in the neck, see a doctor immediately," as these may be signs of a more serious medical issue that requires attention right now, Dr. Chen says.