Not everyone can flare their nostrils on command. In a study of 121 people from the general population, roughly 40% were unable to voluntarily widen their nostrils, even when they tried hard or breathed forcefully through the nose.1PubMed. The lost muscles of the nose That number is surprisingly high, and it points to something more interesting than a simple party trick. The ability to flare depends on a tangle of muscle anatomy, nerve wiring, cartilage shape, and learned motor control that varies quite a bit from person to person.
The Muscles Behind the Flare
Your nostrils are not just passive holes. They are surrounded by a small group of muscles that actively open and close them. The main player is the dilator naris, a thin muscle that fans out across the outer wall of each nostril. When it contracts, it pulls the nostril sideways and open. Working alongside it are the alar part of the nasalis (which anchors to the bone of your upper jaw and attaches to the skin of the nostril wing) and a lesser-known muscle called the dilator naris vestibularis, which sits between the outer skin and the inner lining of the nostril lobule and radiates fibers along the dome-shaped nasal vestibule.2PubMed. New anatomical profile of the nasal musculature: dilator naris vestibularis, dilator naris anterior, and alar part of the nasalis
These muscles are tiny and, in many people, poorly developed. They are not like your biceps or jaw muscles, which you use all day and which respond to obvious mental commands. The nasal muscles sit in a gray zone between voluntary and involuntary control. Electromyography recordings show that the dilator naris and nasalis fire automatically during breathing, ramping up during inhalation to help keep your nasal passages from collapsing inward.3PubMed. Electromyography of the human nasal muscles For some people, that automatic firing is the only thing these muscles ever do. Getting them to fire on purpose is like trying to wiggle your ears: the hardware is there, but the neural pathway for voluntary activation may never have been trained.
Why Some People Cannot Do It
The 40% figure from the study above is not just about willpower or practice. Several factors seem to determine whether a given person can consciously flare.
The first is muscle bulk. Dissection studies have found that the size, fiber density, and attachment points of the nasal dilator muscles vary between individuals. In some people, the alar part of the nasalis is robust and clearly defined; in others, it is wispy or partially fused with surrounding tissue. The same goes for the dilator naris anterior, whose lower insertion point can vary in how far it extends.2PubMed. New anatomical profile of the nasal musculature: dilator naris vestibularis, dilator naris anterior, and alar part of the nasalis If you were dealt thinner nasal muscles, the physical range of motion for your nostril wall may simply be smaller.
The second factor is cartilage architecture. The lower lateral cartilage, which forms the structural skeleton of your nostril, has a three-dimensional shape that differs between people. Research on cadaveric specimens has shown that this cartilage can have a hemispheric, almost dome-like appearance, connected to the upper lateral cartilage by an inward-curving limb. Variations in that inward limb can produce natural asymmetry and influence how much a nostril is able to flare outward.4PubMed. Applied anatomy of the nasal lower lateral cartilage: a new finding In other words, some people’s noses are simply built to flare more easily, while others have cartilage that resists the movement mechanically.
A third factor is neural control. The nasal muscles are innervated by branches of the facial nerve (cranial nerve VII). The strength and precision of voluntary facial-nerve signals to small facial muscles varies enormously between people. This is the same reason some people can raise one eyebrow while others cannot. The motor cortex has to have a clear enough map of those tiny muscles to fire them in isolation, and for many people that map was never finely drawn.
Can You Learn to Flare If You Cannot Already?
Possibly, yes. A small clinical study tested biofeedback training on patients who had weak or ineffective nasal muscle control, specifically people suffering from nasal valve problems that made breathing through the nose difficult. The training used surface electrodes placed on and inside the nose so patients could see their own muscle activity in real time, paired with a home exercise program of specific nasal movements. In about 87% of those patients, nasal muscle function improved enough to relieve their obstructed breathing without surgery.5PubMed. Biofeedback training of nasal muscles using internal and external surface electromyography of the nose – Section: Abstract / Results
That study was focused on clinical outcomes rather than the party-trick version of nostril flaring, but the principle is the same: the nasal muscles can be strengthened and brought under better voluntary control with targeted practice. Whether a healthy person who simply cannot flare would benefit from the same approach is less studied, but the underlying motor-learning mechanism is plausible. The muscles are there; the challenge is building the neural pathway to activate them on demand. Repeated attempts, especially with some kind of visual feedback (even just watching yourself in a mirror), may help over time.
What Nostril Flaring Actually Does for Breathing
Voluntary flaring is not just cosmetic or expressive. When you widen your nostrils, you physically open the nasal valve, the narrowest bottleneck in the nasal airway. A study of 24 healthy adults found that flaring the nostrils reduced nasal airway resistance by a median of about 21%, while pinching them inward increased resistance by roughly 67%.6PubMed. The voluntary control of nasal airway resistance That is a meaningful difference, especially during exertion.
During exercise, the nasal dilator muscles ramp up automatically. Research measuring muscle activity during progressive-intensity workouts found that the dilator naris activated in near-perfect proportion to how much air was being moved through the nose, increasing linearly with nasal ventilation.7PubMed. Influence of nasal airflow and resistance on nasal dilator muscle activities during exercise The harder you breathe, the more the muscles fire to keep the airway open against the sucking pressures of fast airflow. In people whose nasal muscles are weak or poorly innervated, this automatic dilation may be insufficient, and the nostril walls can collapse inward during heavy breathing. This is one reason some people instinctively switch to mouth breathing during hard exercise: their nasal valves cannot keep up.
When the Flare Fails on One Side
Facial paralysis offers a dramatic illustration of how much nostril flaring matters. When the facial nerve is damaged on one side, as happens in Bell’s palsy or after surgery near the parotid gland, the nasal muscles on that side go slack. The nostril wall loses both its resting tone and its ability to dilate, causing it to sag inward and narrow the airway. The alar base (the bottom anchor point of the nostril wing) shifts inward and downward, further constricting airflow.8PubMed. Rhinoplasty: Considerations for Patients with Facial Paralysis
This is not just a cosmetic issue. Patients with bilateral nasal valve weakness, where both sides lack adequate support, tend to have more severe drops in blood oxygen during sleep compared to those with only one weak side or neither.9PubMed Central. The role of the nasal valve in patients with obstructive sleep apnea syndrome Surgeons addressing facial paralysis sometimes use cartilage grafts, flaring sutures, or fascial sling techniques to prop the nostril open mechanically, essentially doing what the paralyzed muscles no longer can.8PubMed. Rhinoplasty: Considerations for Patients with Facial Paralysis
Nasal Flaring as a Clinical Warning Sign
If you have ever watched a doctor examine a child in respiratory distress, one of the first things they look for is whether the nostrils are flaring with each breath. In that context, flaring is involuntary; the body is automatically throwing every available airway-opening muscle into the fight to get enough oxygen. A study of children presenting to a pediatric emergency department with acute respiratory infections found that nasal flaring was one of the most sensitive signs of dangerously low blood oxygen, picking up about 84% of cases. It was also the best standalone predictor of hypoxemia among the signs assessed, with a positive predictive value of 53%.10PubMed. Clinical predictors of hypoxemia in Indian children with acute respiratory tract infection presenting to pediatric emergency department
This involuntary flaring is worth distinguishing from the voluntary kind. When a person in respiratory distress flares their nostrils, the nasal dilator muscles are being driven hard by brainstem respiratory centers that have detected rising carbon dioxide or falling oxygen in the blood. It is the same neural circuit that fires these muscles during normal breathing, just cranked up to emergency levels. Even people who cannot voluntarily flare may still exhibit this involuntary flaring during serious breathing difficulty, because the reflex pathway bypasses the voluntary motor cortex entirely.
Nostril Flaring and Emotional Expression
Beyond breathing, nostril flaring plays a role in how we communicate emotions nonverbally. The nostrils tend to widen involuntarily during states of anger, fear, and sexual arousal, driven by sympathetic nervous system activation that shifts blood flow in the nasal tissues and triggers the dilator muscles.11Journal of Clinical Respiratory Medicine. The Silent Language of Emotion: Exploring the Meaning Behind Nose Flaring People read these cues intuitively. Research on the perception of anger faces found that each individual component of a classic angry expression, including the nose flare by itself, led observers to judge the person making the face as physically stronger and more formidable.12University of California – Santa Barbara. The universal ‘anger face’: Each element makes you look physically stronger and more formidable
This gives nostril flaring a dual social life. In anger, it signals threat. In exertion, it signals effort. In fear, it signals alarm. All of these trigger the same muscle group but for different upstream reasons, whether a surge of adrenaline, a brainstem respiratory drive, or a cortical motor command when you are just showing off at a party. The 40% of people who cannot voluntarily flare can still experience these involuntary emotional flares, because again, the automatic circuits are separate from conscious control.
Nose Shape, Ethnicity, and the Range of Normal
The geometry of the nose itself affects how visible and how mechanically effective a flare can be. Nasal morphology varies considerably across populations. Computational modeling of nasal anatomy across racial and sex categories has shown differences in internal surface area, cavity volume, and nasal index (the ratio of nose width to height). In the modeled populations, Black individuals had the largest median nasal index, while Caucasian individuals had the smallest, and males had significantly larger internal nasal cavity volumes and surface areas than females.13PubMed Central. The Role of Normal Nasal Morphological Variations from Race and Gender Differences on Respiratory Physiology
A wider nose with more laterally positioned alar cartilages may produce a more dramatic visible flare simply because there is more soft tissue lateral excursion available. A narrower nose with stiffer or more vertically oriented cartilage may flare just as effectively in terms of opening the nasal valve, but the movement may be harder to see. None of this means that people from one population are “better” at flaring than those from another. It means that the same muscle contraction can look quite different on different faces, and the ease of the movement depends partly on the structural hand you were dealt.
Why the 40% Probably Is Not the Final Word
The study finding that 40% of people cannot voluntarily flare their nostrils is the most commonly cited figure on this question, and it comes from a well-designed observational study published in a plastic surgery journal.1PubMed. The lost muscles of the nose But it is a single study of 121 people, and the researchers noted that they were evaluating both deliberate voluntary flaring and subconscious flaring during forceful nasal breathing. Some of those 40% may have muscles capable of flaring but no conscious access to them; others may have muscles that are genuinely too weak or poorly attached to produce visible movement.
No large-scale follow-up has been done, partly because the question does not attract much research funding. The true population percentage of non-flarers could be somewhat higher or lower depending on how strictly you define the movement and what population you sample. Age may matter as well: nasal cartilage stiffens with age, and muscle bulk tends to decline. A teenager and a seventy-year-old with identical nasal anatomy at birth might differ substantially in flaring ability by the time they are tested.
External Nasal Dilators and Mechanical Workarounds
The billion-dollar nasal strip industry exists precisely because many people’s nasal muscles do not do an adequate job of keeping the valve open. Adhesive strips like Breathe Right and their competitors work by physically pulling the nostrils outward, mimicking the action of the dilator naris without requiring any muscle activation at all. Athletes, snorers, and people with nasal valve collapse use them to bypass what the muscles cannot deliver.
Internal nasal dilators, small plastic or silicone cones inserted into the nostrils, serve the same function from the inside. These are not treatments for the inability to voluntarily flare per se, but they highlight how functionally important nostril dilation is. When the 21% reduction in airway resistance from voluntary flaring is unavailable to someone, a mechanical device can approximate or exceed that benefit.6PubMed. The voluntary control of nasal airway resistance For athletes performing at high intensities, even modest improvements in nasal airflow can make the difference between comfortable nasal breathing and having to switch to the mouth.
The Asymmetry Question
Even among people who can flare, most notice that one side moves more than the other, or that they can flare on one side but not both equally. This is normal and expected. The nasal lower lateral cartilages are rarely perfectly symmetrical, and the inward limb connecting them to the upper lateral cartilage can differ in curvature and rigidity between sides.4PubMed. Applied anatomy of the nasal lower lateral cartilage: a new finding Facial nerve branching patterns are also asymmetric in most people, delivering slightly different signal strength to the left and right nasal muscles. The result is that truly symmetrical, dramatic bilateral flaring, the kind actors do in movies, represents one end of a spectrum. Many people’s version is lopsided, subtle, or limited to one nostril.
If you have always been able to flare on both sides but suddenly lose the ability on one, that is a different situation. Sudden unilateral loss of nasal muscle function can signal facial nerve damage and warrants medical attention. But lifelong asymmetry in voluntary flaring is just anatomy being its messy, imperfect self.