Feeling like you smell can mean one of two very different things: either your body is actually producing a stronger odor than usual, or your brain is perceiving a smell that other people can’t detect. Both are surprisingly common, and figuring out which one applies to you is the first step toward fixing it.
Your Brain May Be Creating the Smell
Phantom smells, known clinically as phantosmia, affect roughly 5% of older adults in the general population, and the condition spans all age groups. With phantosmia, you detect an odor that genuinely isn’t there. Most people describe these phantom smells as unpleasant: burning rubber, garbage, rotting food, smoke, chemicals, or something metallic. Some people smell something they can’t quite identify. Either way, the experience feels completely real because your olfactory system is actually firing, just without an external trigger.
The most common causes are everyday issues like colds, sinus infections, allergies, and nasal polyps. Migraines are another frequent culprit. Many people developed phantosmia after a COVID-19 infection, and for some it has lingered for months or longer. Certain medications, smoking, dental problems like gum disease, and exposure to chemicals such as lead or mercury can also trigger it. Less commonly, phantom smells can signal neurological conditions like Parkinson’s disease, epilepsy, or head trauma, but these typically come with other noticeable symptoms.
Heightened Smell Sensitivity
Sometimes the issue isn’t a phantom odor but an amplified real one. Hyperosmia is a condition where your sense of smell becomes unusually sharp, making normal body scents or environmental odors feel overpowering. You might suddenly notice your own skin, hair, or clothes in a way you never did before.
Pregnancy is one of the most recognized triggers. One study found that 67% of pregnant women reported increased smell sensitivity in early pregnancy, with 17% experiencing distorted smells and 14% reporting phantom smells. Migraines can produce the same effect between attacks, with some people becoming so sensitive to odors that certain smells actually trigger their next episode. Epilepsy, abrupt drug withdrawal, and head injuries have also been linked to periods of heightened smell perception. If you’re a woman of childbearing age who suddenly feels like everything smells stronger, pregnancy is worth considering as a cause.
When You Actually Do Smell Different
Body odor starts with sweat, but sweat itself is essentially sterile when it leaves the gland. The smell comes from bacteria on your skin breaking down the fatty acids in sweat, producing short-chain fatty acids and ammonia. The areas with the most concentrated sweat glands, particularly the armpits, are where this process is strongest. When bacteria like Clostridium perfringens interact with sweat, the result is that characteristic body odor.
Several things can shift this process into higher gear. Hormonal changes during puberty, menstruation, pregnancy, or menopause all alter sweat composition and can change how you smell. Stress sweat, which comes from a different type of gland than heat-related sweat, tends to produce a stronger odor. Poor hygiene is the obvious factor, but even with regular washing, changes in diet, medication, or health status can make a real difference.
Diet and Metabolic Causes
What you eat directly affects how you smell. Low-carb and ketogenic diets cause your body to burn fat for fuel, producing compounds called ketone bodies. One of these, acetone, is volatile and gets exhaled through your lungs, creating a distinctive fruity or nail polish-like odor on the breath. This “keto breath” is a normal metabolic byproduct, not a sign of poor hygiene, but it’s noticeable to others.
A rarer but more dramatic example is trimethylaminuria, sometimes called fish odor syndrome. People with this condition can’t fully break down a compound called trimethylamine, which is produced by gut bacteria during digestion of eggs, fish, liver, and legumes. The result is a strong fishy smell in sweat, breath, and urine. It’s caused by variants in a specific gene (FMO3), and symptoms can be worsened by stress or dietary choices. If you’ve noticed a persistent fishy smell that doesn’t respond to normal hygiene, this is worth discussing with a doctor.
The Anxiety and Obsession Loop
There’s a psychological dimension to this that affects more people than you might expect. Olfactory reference syndrome is a condition where someone becomes preoccupied with the belief that they emit a foul odor, even though others can’t smell anything. The core feature is a persistent, distressing conviction that you smell bad, combined with repetitive behaviors: sniffing yourself, showering excessively, reapplying deodorant constantly, or trying to camouflage a perceived odor.
People with this condition typically experience intense shame, embarrassment, and anxiety in social situations. Many begin avoiding other people altogether. The thoughts about the odor become intrusive and obsessive, similar to what happens in OCD. Insight varies widely. Some people recognize intellectually that the smell probably isn’t real but can’t shake the feeling. Others become completely convinced. If you find yourself constantly checking whether you smell, asking others for reassurance, or withdrawing from social life because of odor concerns that nobody else confirms, this pattern is worth taking seriously as its own treatable condition rather than just an odor problem.
Sinus and Nasal Problems
Chronic sinus inflammation can distort your sense of smell in ways that make you think you’re the source of a bad odor. When the nasal passages are inflamed or blocked by polyps or swelling, the signals reaching your smell receptors get scrambled. This can produce parosmia, where real smells get distorted into something foul, or it can reduce your ability to accurately gauge your own scent. Sinus infections themselves can also produce genuinely foul-smelling mucus drainage that you detect but others may not, creating the impression that you smell bad when the odor is actually coming from inside your nasal cavity.
How to Tell If the Smell Is Real
The simplest test is asking someone you trust. This sounds obvious, but many people who worry about their smell never actually verify it with another person, either because they’re embarrassed or because they assume others are just being polite. A direct, honest answer from a close friend or family member is more useful than any amount of self-sniffing.
Beyond that, pay attention to patterns. A smell that only you notice, that comes and goes without a clear trigger, or that persists even right after a shower is more likely to be phantosmia or a perception issue. A smell that’s strongest in specific body areas, that worsens with heat or exercise, and that others can confirm points toward an actual odor issue. If the smell seems to come from inside your nose rather than from your skin or clothes, sinus problems or phantosmia are more likely causes.
Hormonal timing matters too. If the perception shifts with your menstrual cycle, started during pregnancy, or coincided with menopause, hormonal changes in smell sensitivity are a likely explanation. Women after menopause show a measurable decline in olfactory ability compared to premenopausal women, which means smell perception genuinely shifts with hormonal status throughout life.