Why Does My Husband Smell Musty?

A musty body odor almost always traces back to bacteria on the skin breaking down compounds in sweat and sebum, the oily substance your skin naturally produces. The specific “musty” or “stale” quality, as opposed to a sharp sour smell, usually points to a particular group of bacteria acting on secretions from sweat glands concentrated in the armpits, groin, and chest. But the reasons that smell has become noticeable, or changed from what you remember, can involve anything from his wardrobe fabric to shifting hormone levels to an underlying health issue worth paying attention to.

Where the Smell Actually Comes From

Fresh sweat is nearly odorless. The smell develops when bacteria that live on the skin get to work on it. Research has shown that a specific group of bacteria called diphtheroids, rather than other common skin residents, are responsible for generating what we recognize as typical body odor when they encounter secretions from apocrine sweat glands.¹ Other bacteria on the skin, like cocci, tend to produce a different, more sharply “sweaty” smell linked to a compound called isovaleric acid. The musty, slightly greasy quality you’re picking up is more characteristic of the diphtheroid bacteria processing the fats and proteins in apocrine sweat.

This matters because it explains why some people smell sharper or more sour while others have that heavier, musty tone. It is not just about sweating more or less. The specific bacterial community living on your husband’s skin, combined with the composition of his sweat, determines the character of the odor. And that bacterial community is shaped by everything from his genetics to his clothing to how warm and damp his skin stays during the day.

Why His Clothes Might Be the Real Culprit

If the musty smell seems to linger even after your husband showers, his wardrobe could be a major factor. Synthetic fabrics like polyester hold onto odor-causing bacteria far more stubbornly than natural fibers. A study that had people wear either polyester or cotton shirts during exercise found that the polyester shirts smelled significantly worse afterward, with a type of bacteria called Micrococci growing almost exclusively on the synthetic fabric.² The structure of synthetic fibers gives odor-producing microbes a better surface to colonize, and standard washing doesn’t always clear them out.

Laundry habits compound the problem. Research into what happens to clothing after washing at moderate temperatures (around 86°F or 30°C, a common “cold wash” setting) found that skin bacteria survived the wash cycle and, during prolonged drying, produced intense odors dominated by branched fatty acids with an animal-like smell.³ Cotton fabrics actually harbored more bacteria in the wash water and produced stronger smells than polyester in that study, meaning the laundry-to-closet pipeline can reintroduce mustiness regardless of fiber type if the wash temperature is too low or clothes sit damp for too long.

Practically speaking, if his gym shirts or undershirts smell musty straight out of the drawer, the bacteria have colonized the fabric itself. Washing at a higher temperature, using an oxygen-based laundry booster, or switching to more cotton or merino wool for everyday wear can make a noticeable difference.

The Aging Factor

If your husband is in his forties or older, part of what you’re smelling could be a genuine chemical change in his skin. A compound called 2-nonenal, which has a greasy, musty, sometimes grassy odor, increases in concentration on the skin as people age. Research found that 2-nonenal is produced when certain unsaturated fatty acids naturally present on the skin’s surface are broken down through oxidation.⁴ In Japanese culture, this phenomenon even has its own word, “kareishū,” roughly translating to “aging smell.”

This is not something your husband can simply wash away, because the fatty acids on his skin are constantly being replenished and oxidized. Regular bathing helps reduce the concentration, and some people find that products containing persimmon tannin or polyphenol-rich body washes help neutralize 2-nonenal. But to some degree, a shift in body odor character with age is a normal biological process, not a hygiene failing.

Hormones and Oil Production

Androgens, the group of hormones that includes testosterone, directly stimulate the sebaceous glands in the skin, increasing the production of sebum, the oily substance that coats the skin and hair.⁵ More sebum means more raw material for skin bacteria to feast on, which means more odor. This is one reason men tend to have stronger body odor than women on average: higher androgen levels drive more sebum production.

Hormonal shifts can happen at different life stages and for different reasons. Weight gain increases the conversion of certain hormones in fat tissue. Stress raises cortisol, which can affect other hormone pathways. Even sleep disruption can alter hormone balance over time. If your husband’s odor has changed alongside other shifts like weight gain, increased stress, or changes in energy levels, the hormonal connection is worth considering, and a doctor can check hormone levels with a simple blood test.

Stress Sweat Smells Different

You might have noticed that your husband smells different after a stressful workday compared to after a run. That is not your imagination. The sweat produced during emotional stress comes partly from apocrine glands, which release a thicker, more protein-rich fluid than the watery eccrine sweat produced during exercise. Research has identified that during confirmed stressful situations, skin emits compounds including allyl mercaptan and dimethyl trisulfide, producing a distinctive and recognizable odor.⁶

If the musty smell is worst when your husband comes home from a high-pressure job, or during periods of anxiety, stress sweat is likely contributing. This type of odor responds less well to conventional antiperspirants (which target eccrine sweat glands) and more to managing the stress itself, wearing breathable fabrics, and showering soon after the stressful period ends.

Diet and What the Body Processes

What your husband eats influences what his skin excretes. The gut breaks down certain foods into volatile compounds that are then released through sweat and breath. Interestingly, not all pungent foods make body odor worse. A study testing the effect of garlic found that at higher doses, the body odor of men who ate garlic was actually rated as more pleasant and attractive by women evaluators, and less intense overall.⁷ The researchers speculated that garlic’s antimicrobial properties might alter the skin’s bacterial ecosystem in a favorable way.

Foods more commonly associated with unpleasant body odor include cruciferous vegetables (broccoli, cabbage, cauliflower) in large quantities, red meat, heavily processed foods, and alcohol. Alcohol is metabolized partly through the skin, and heavy or frequent drinking can produce a stale, slightly sweet-musty scent that many partners notice. A high-sugar diet can also feed yeast on the skin, contributing to that damp, musty quality.

Yeast on the Skin

Beyond bacteria, a yeast called Malassezia lives on virtually everyone’s skin and feeds on the oils there. When it overgrows, especially in warm, moist areas like the chest, back, and scalp, it can contribute to a musty or slightly sour smell. Analysis of the volatile compounds produced by Malassezia furfur has shown that it generates a range of odor molecules including alcohols and ketones, with hexan-1-ol being one of the most consistently detected across growth conditions.⁸

Malassezia overgrowth often accompanies dandruff, seborrheic dermatitis (flaky, red patches on the scalp, eyebrows, or chest), and a condition called tinea versicolor, where patches of skin become lighter or darker. If your husband has any of these alongside the musty smell, the yeast component is likely significant. Antifungal body washes containing ketoconazole or zinc pyrithione, used a few times per week, can help bring the yeast population back into balance.

Medical Conditions That Change Body Odor

Sometimes a persistent musty smell points to something that deserves medical attention. Liver problems can alter body odor distinctly. Analysis of breath compounds in patients with liver disease found elevated levels of dimethyl sulfide, acetone, 2-butanone, and 2-pentanone compared to healthy individuals.⁹ Dimethyl sulfide, in particular, has a musty, slightly cabbage-like quality. A condition sometimes called “fetor hepaticus” produces a characteristically musty or sweet-musty breath that is recognized as a clinical sign of liver dysfunction.

Diabetes and related metabolic disorders also shift the chemical profile of sweat and urine. Research has identified that patients with diabetes being treated with insulin show abnormally high levels of certain volatile compounds in their urine, including cyclohexanone and various alcohols, that differ markedly from the profile in healthy individuals.¹⁰ Poorly controlled blood sugar can produce a fruity or musty body odor that is distinct from ordinary sweat.

Kidney disease can lead to a buildup of urea in the body, sometimes giving sweat an ammonia-like or stale quality. And a rarer genetic condition called trimethylaminuria causes the body to accumulate trimethylamine, a compound with a strong fishy or musty odor, because a liver enzyme called FMO3 is not working properly and cannot convert the smelly compound into its odorless form.¹¹ People with this condition excrete trimethylamine through their breath, sweat, and urine.¹² While rare in its full-blown form, milder versions exist where the enzyme works but not efficiently, producing a less dramatic but still noticeable musty or fishy undertone that worsens after eating foods rich in choline, like eggs, fish, and organ meats.

If the musty smell is new, persistent despite good hygiene, and especially if it’s accompanied by other symptoms like fatigue, changes in urine color, unexplained weight changes, or digestive issues, a visit to the doctor is warranted. Simple blood and urine tests can screen for liver, kidney, and metabolic issues.

Medications That Alter Body Odor

Certain prescription drugs can change how a person smells. A documented case involved a patient taking empagliflozin, a diabetes medication that works by causing excess sugar to be excreted in the urine. Within two weeks of starting the drug, the patient noticed a foul body odor that disappeared a week after stopping the medication.¹³ This class of drugs (SGLT2 inhibitors) increases sugar in urine, which can promote bacterial and yeast growth in the genital area and on the skin.

Other medications associated with body odor changes include certain antidepressants (which can increase sweating), supplements like fish oil or high-dose B vitamins, and antibiotics (which alter gut and skin bacterial populations). If the musty smell started around the same time as a new medication, that connection is worth raising with his prescribing doctor.

The Bedroom Itself

Sometimes the musty smell you associate with your husband is partly environmental. Pillows, mattresses, and bedding accumulate sweat, skin cells, and fungi over time. A study examining used pillows found a surprisingly diverse fungal population, with anywhere from four to sixteen different species isolated per pillow, including Aspergillus fumigatus, a common mold associated with musty odors. Synthetic pillows actually harbored a greater number of fungal species than feather pillows.¹⁴

If the musty smell is strongest in the bedroom or on bedding, the pillows and mattress deserve attention. Pillows should be replaced every one to two years, mattresses should have a washable protector, and bedding should be washed weekly at a temperature high enough to kill fungi and bacteria. Airing out the bedroom by opening windows during the day can also reduce moisture buildup that encourages microbial growth.

Breath Can Smell Musty Too

What you’re interpreting as body odor might partly be coming from your husband’s mouth. Oral malodor is caused by bacteria in the mouth breaking down proteins and amino acids, which produces volatile sulfur compounds like hydrogen sulfide, methyl mercaptan, and dimethyl sulfide.¹⁵ Poor oral hygiene, gum disease, and a coated tongue are the most common causes. Dimethyl sulfide in particular has a musty, slightly vegetable-like quality that can be perceived as a general “staleness” rather than obvious bad breath, especially when you’re close to someone.

Nasal and sinus issues can also produce a musty odor that seems to come from the whole person. Chronic sinusitis, nasal polyps, and post-nasal drip all create an environment where bacteria thrive and produce smelly compounds. If the smell seems concentrated around his face and head, a dental checkup and possibly a visit to an ENT specialist could be revealing.

Why You Might Be Noticing It Now

There is a real possibility that your husband has always smelled this way, and your nose has simply stopped filtering it out. The olfactory system is wired for habituation, a process by which repeated exposure to the same odor leads to a decreased response to it.¹⁶ You become “nose-blind” to the smells you encounter constantly, which is why you can’t smell your own home the way a visitor can. If you’ve been apart for a while (a business trip, visiting family separately, even sleeping in different rooms during an illness), you can temporarily lose that habituation, and suddenly his normal scent registers as strong or unpleasant.

Hormonal changes on your end can also shift your olfactory sensitivity. Pregnancy famously heightens smell perception, but fluctuations across the menstrual cycle, perimenopause, and even changes in your own medication or diet can alter how sensitive your nose is and how you perceive familiar odors. Before concluding that he has changed, it is worth considering whether your perception has.

The Immune System Connection to Scent Preference

There is a well-studied link between immune system genetics and how attracted people are to each other’s body odor. Research has shown that people tend to prefer the scent of partners whose major histocompatibility complex (MHC) genes differ from their own. In one study, men and women who were reminded of their own partner or ex-partner when smelling a stranger’s worn T-shirt had significantly fewer MHC alleles in common with that T-shirt wearer than would be expected by chance.¹⁷ The finding suggests that the MHC complex influences mate selection partly through scent.¹⁸

This is relevant because hormonal contraceptives have been shown in some research to alter scent preferences. If you started or stopped hormonal birth control at some point during your relationship, your baseline olfactory preferences could have shifted. It does not mean your husband’s scent is “wrong” for you in some deep biological sense, but it is an additional variable that can influence whether his natural odor strikes you as pleasant, neutral, or musty.

Practical Steps Worth Trying

Addressing a musty body odor usually works best as a layered approach, because multiple contributing factors are often at play simultaneously:

• Fabric audit: Replace synthetic workout clothes and undershirts with cotton, merino wool, or other natural fibers. Wash workout gear at higher temperatures or add a cup of white vinegar to the rinse cycle to kill embedded bacteria.
• Targeted washing: An antibacterial or antifungal body wash used on the armpits, chest, and groin a few times a week can reduce both bacterial and yeast populations on the skin. Benzoyl peroxide wash, typically sold for acne, is particularly effective at reducing odor-causing bacteria.
• Bedding refresh: Replace pillows if they are more than two years old, wash sheets weekly at 140°F (60°C) or higher, and use a waterproof mattress protector that can be laundered.
• Diet check: Reducing alcohol, heavily processed foods, and very high-protein diets can lower the intensity of body odor. Increasing vegetables and fruits supports a less volatile metabolic profile.
• Medical screening: If the smell is new, persistent, or accompanied by other symptoms, blood tests for liver function, kidney function, blood sugar, and thyroid levels are a reasonable starting point.

The conversation with your husband is often the hardest part. Framing it around health concern rather than complaint tends to land better. “I’ve noticed your smell has changed and I want to make sure nothing is going on” is a different message than “you smell bad,” even if the underlying observation is the same.