Same Age, but My Husband Has an ‘Aging Smell’ (2-Nonenal): What Causes It, Why Men Notice It More, How to Wash and Launder, How to Bring It Up Kindly, and Which Odors Need a Doctor

Reader question: we are the same age, so why does my husband have an aging smell, and how do I tell him without hurting him?

A member of a women’s 40+ group shared that she and her husband are the same age, but lately he has a body odor of the kind the Japanese call “kareishu” (aging smell) that clings to him and his clothes most of the time.
She wants to tell him but worries he will lose confidence, so she asked what causes it, why it shows up more in him, and how to care for it.

Short answer: age-related odor does not mean poor hygiene. It is a chemical change in skin fats with age. It can be reduced by washing oil-rich areas, caring for clothes and bedding, and adjusting diet.
When you talk about it, start from “we are both entering this stage”, not from cleanliness.
If you are having night sweats or hot flashes yourself, read
early menopause at 41, night sweats and hormone tests

1. What causes age-related odor at 40+: the chemistry of 2-nonenal

Direct answer: with age, skin oil (sebum) contains more omega-7 fatty acids and lipid peroxides. When these fats oxidize, they break down into 2-nonenal, an aldehyde with a greasy, grassy smell.

The original study: detected only in people aged 40 and over

Researchers analyzed body odor from volunteers aged 26–75 and found 2-nonenal only in those aged 40 or older. The amount of 2-nonenal correlated with omega-7 fatty acids and lipid peroxides on the skin.
When skin fats were oxidized in the lab, 2-nonenal formed only from omega-7 fatty acids
(Haze 2001).
In short, the original study found that 2-nonenal forms when omega-7 fats on the skin oxidize.

2-nonenal rises in both men and women

Measurements of skin emissions at the nape, where oil and sweat glands are dense, showed that 2-nonenal rises with age in both men and women
(Kimura 2016).
Another study identified nearly 100 volatile compounds from the back and forearm skin of 25 volunteers, some of which changed with age. Body odor is a blend of many compounds, not 2-nonenal alone
(Gallagher 2008).

Middle-age odor (diacetyl) is different from 2-nonenal

Diacetyl at the nape smells buttery or like old cooking oil. The same study found it peaks in the 30s, falls after 40, and occurs in both sexes
(Kimura 2016).
Underarm odor is another mechanism: Corynebacterium bacteria break down secretions from apocrine sweat glands
(James 2013).

Table: telling age-related, underarm and disease-related odors apart

Use this for first observations and to prepare questions for a doctor. Odor alone cannot confirm a disease.

2. Why the odor is stronger in the husband when both are the same age

Direct answer: skin oil is the raw material for 2-nonenal. Men keep producing sebum at the same level until about age 80, while women’s output falls after menopause, so a couple of the same age carry different amounts of raw material on their skin.

Androgens drive the oil glands

A study of oil glands across the lifespan found that sebum output rises from late childhood under androgens and then plateaus after the teens.
In men, sebum levels barely change until about age 80
(Pochi 1979).

Women’s sebum output falls after menopause

In women, sebum output declines gradually after menopause, which the researchers linked to lower androgen production
(Pochi 1979).
Also, people who live together get used to their own smell but notice their partner’s more easily.

Women can have age-related odor too

Measurements at the nape showed 2-nonenal rising with age in women as well
(Kimura 2016).
During menopause many women have hot flashes and night sweats, which leave clothes and bedding damp more easily, so the care in this guide applies to both partners.

Age-related odor is not always stronger

In an experiment, 41 young adults smelled body odors from 3 age groups. Odors from people aged 75–95 were rated less intense and less unpleasant than odors from people aged 20–30 and 45–55
(Mitro 2012).
Odor differs by age, but older people do not necessarily smell stronger.

3. How to wash, and how much persimmon or green tea soap helps

Direct answer: regular soap helps remove the skin-surface lipids that 2-nonenal comes from. The key is to reach the nape, behind the ears, the chest and the upper back, which people often miss.
Persimmon or green tea soaps are optional extras; no human study has measured their effect on 2-nonenal on skin.

Areas to reach when washing

• Nape, behind the ears and the ears: lather and rub with fingers or a small washcloth every shower
• Chest and upper back: use a cloth or a soft long-handled brush to reach the middle of the back; do not scrub until red
• Scalp: wash hair regularly, because the nape and scalp have dense oil glands
• After heavy sweating: shower or wipe down and change clothes after exercise, outdoor work or before bed
• Dry thoroughly: especially skin folds, then wear fully dried clothes
• Dry skin after bathing: use a light lotion; heavy body oils on the nape and back are not needed

Evidence on persimmon soap, green tea and antioxidants

Persimmon tannin is a polyphenol that binds odor molecules in the lab. The published PubMed research is on bad breath: a 0.1% persimmon tannin gel reduced sulfur compounds that cause mouth odor in dogs
(Toyooka 2025).
Eggplant extract captured 2-nonenal in the test tube
(Kim 2025).
But no human study has measured how much persimmon soap lowers 2-nonenal on skin. If you want to try one, patch-test it on the inner forearm for 2–3 days and stop if it stings or causes a rash.

Antiperspirants help the underarms but not the nape

Aluminium-salt antiperspirants and deodorants help underarm odor, which comes from bacteria breaking down sweat
(James 2013).
2-nonenal comes from skin oil on the nape and upper body, so perfume or antiperspirant alone does not cover age-related odor.

4. Can diet reduce age-related body odor?

Direct answer: small trials found that eating less red meat and taking fruit polyphenols changed body odor, but no long-term trial shows that diet resolves age-related odor. Use it alongside washing and clothing care.

Less red meat, less unpleasant odor

Seventeen men alternated 2 weeks with and without red meat. Thirty women smelled their underarm samples blind and rated the no-red-meat period as more pleasant and less intense
(Havlicek 2006).

Fruit polyphenols lowered 2-nonenal in a small trial

Fourteen adults, average age 55 ± 5, took 6 g of blackcurrant powder daily for 7 days. Six skin compounds at the base of the neck, including 2-nonenal, fell by more than 25% compared with no intake
(Willems 2022).
The trial was small and short, so it shows that diet affects skin emissions; it is not a reason to buy any particular fruit powder.

• Colorful fruit and vegetables: at least 5 servings a day, such as guava, oranges, tomatoes, leafy greens and eggplant
• Less red meat and re-fried food: swap in fish, eggs, tofu and beans
• Green tea or water: fine instead of sweet drinks, but no study shows green tea directly reduces age-related odor
• Alcohol and smoking: cut down or quit for overall health, although no trial has measured the effect on 2-nonenal directly

5. How to wash and dry clothes so odor does not build up

Direct answer: shirt collars, pillowcases and sheets hold skin oil and odor-causing microbes. Washing in warm water where the label allows, using an enzyme detergent for cold washes, and drying quickly all reduce buildup.

Synthetic fabric holds more odor than cotton

Researchers collected shirts from 26 people after an intense cycling session. Polyester shirts smelled stronger and less pleasant than cotton ones, because some microbes grow better on synthetic fibers
(Callewaert 2014).
Another study in 10 men found that washing with a mild detergent changed the microbes on shirts only a little
(Sterndorff 2020).

Water temperature and enzymes

A review of laundry science concluded that temperature plays the main role in controlling microbes, requiring 40–60 °C or more. Below 20 °C, enzyme detergents or oxygen bleach become essential
(Abney 2021).

Dry quickly

A 2025 study found that washing reduces odor compounds, but clothes that dry slowly in humid conditions develop a characteristic musty odor and certain microbes increase
(Díez López 2025).
In a humid climate, drying in wind or sun and not leaving wet laundry in the machine matter as much as washing.

• Pillowcases and sheets: wash weekly; pillowcases may need changing more often because they touch the nape every night
• Collared shirts and undershirts: wash after one wear; rub detergent into the collar before machine washing
• Warm water: use 40–60 °C when the label allows; for cold washes use an enzyme detergent
• Hang immediately: take laundry out as soon as the cycle ends and dry it in wind or sun until fully dry
• Choose cotton: for sleepwear and clothes worn at home
• Clean the washing machine: leave the lid open to dry after use and clean the drum as the manual describes

6. How to talk with your partner without hurting his feelings

Direct answer: start from the chemistry of age that affects you both, not from cleanliness. Choose a private moment and suggest changing routines together.

Why talking about odor feels so sensitive

Body odor is tied to feelings about cleanliness and attractiveness. Research in people with a genetic fishy-odor condition found the odor can lead to social isolation and depression
(Mackay 2011).
Age-related odor is far milder, but words that feel like blame can still dent confidence.

• Use “we” or “I” sentences: such as “I’d like to try a new way of doing our laundry” instead of “you smell”
• Talk about what can be done: mention areas to wash or clothes to launder rather than how strong the odor is
• Do not tease: do not compare the odor to objects, and do not tell other people
• Be honest: if you buy a new soap, say plainly that you bought it to try together; there is no need to claim effects that are not true

If odor is part of growing distance in your relationship around menopause, read
intimacy and marriage around menopause

7. When body odor should be checked by a doctor

Direct answer: age-related odor changes over years and has no other symptoms. If an odor changes quickly, has a specific character, or comes with heavy sweating and whole-body symptoms, look for a cause.

Odors linked to disease

Diabetes: diabetic ketoacidosis (DKA) gives the breath a fruity or nail-polish-remover smell, together with vomiting, abdominal pain, deep rapid breathing and drowsiness. It is an emergency
(Umpierrez 2024).
Fruity breath with vomiting, deep rapid breathing or drowsiness needs emergency care.

Liver: a study of 52 liver patients and 50 healthy volunteers found that musty-sweet breath (fetor hepaticus) comes mainly from dimethyl sulfide
(Van den Velde 2008).

Kidney: ammonia and other breath compounds accumulate as kidney function falls and drop after dialysis
(Pagonas 2012).
This odor usually appears in late-stage kidney disease along with other symptoms such as swelling, itching and nausea. Read more in
silent stage 3–4 chronic kidney disease

Fishy odor: trimethylaminuria occurs when the liver cannot efficiently convert TMA into odorless TMAO. It is diagnosed with a urine test after a sea-fish meal and can improve with dietary changes
(Mackay 2011).

Heavy sweating that starts after 40

Heavy sweating that begins after 40, especially over the whole body, often has another cause, such as an overactive thyroid, diabetes, infection, certain medicines or menopause
(Behinaein 2025).
More sweat leaves clothes damp and lets odor build up more easily.

• Annual check-up: blood sugar (fasting glucose or HbA1c), liver and kidney function, and thyroid if there are palpitations or weight loss
• Review medicines: tell a doctor or pharmacist if sweating or odor changed after starting a new medicine
• Mouth: if the odor comes mainly from the mouth, see a dentist, because gum disease is a common cause of bad breath
• Rash or wound: odor from a skin fold or a wound with a red moist rash may be a treatable fungal or bacterial infection

Table: comparing ways to manage age-related body odor

Products are named by type or ingredient only. No method makes age-related odor go away permanently.

Common beliefs versus the evidence

Age-related odor means someone does not wash properly

Not true. 2-nonenal comes from skin fats that are produced and oxidized throughout the day; people who bathe daily can still have it.

Regular soap cannot remove 2-nonenal at all

Not true. Regular soap removes skin fats; the common problem is not reaching the nape, behind the ears and the upper back.

Persimmon soap captures almost all of the aging smell

No human trial has measured this. The available data come from lab tests and a dog bad-breath study.

Aging smell only happens to men

Not true. 2-nonenal rises with age in both sexes, but men keep producing sebum at the same level, so it is often more noticeable in them.

Perfume is enough

Perfume masks odor temporarily but does not reduce the source, and perfume mixed with body odor can smell stronger.

Drinking green tea every day will make the aging smell go away

No human study shows green tea directly reduces age-related odor. It can replace sweet drinks, but skin and clothing care still matter.

Frequently asked questions (FAQ)

What is the aging smell (2-nonenal), and what causes it?

2-nonenal is an aldehyde with a greasy, grassy smell that forms when omega-7 fatty acids in skin oil oxidize. The original study of volunteers aged 26–75 detected it only in people aged 40 and over, mostly on the nape, behind the ears, the chest and the upper back.

Why does my husband smell more than me when we are the same age?

Skin oil is the raw material for 2-nonenal. Men keep producing sebum at the same level until about age 80, while women’s output falls after menopause. Partners also get used to their own smell but notice each other’s more easily. Women’s 2-nonenal can rise with age too.

Does an aging smell mean someone is unclean or ill?

No. Age-related odor is a chemical change in skin fats with age, and people who bathe daily can have it. But if the odor changes within a few weeks, smells fishy, the breath smells fruity, or heavy sweating comes with fever or weight loss, see a doctor.

Can regular soap remove the aging smell, and do persimmon or green tea soaps really work?

Regular soap removes the skin oil that 2-nonenal comes from, as long as you reach the nape, behind the ears, the chest and the upper back. Persimmon or green tea soaps are optional extras; the data come from lab tests and a dog bad-breath study, and no human trial has measured their effect on 2-nonenal on skin.

How should I wash clothes and pillowcases to stop odor building up?

Wash pillowcases and sheets weekly and collared shirts after one wear. Use 40–60 °C water when the label allows, or an enzyme detergent for cold washes. Take laundry out of the machine right away and dry it in wind or sun until fully dry. Cotton holds less odor than polyester.

Can diet reduce age-related body odor?

Somewhat, based on small trials. Men who skipped red meat for 2 weeks had more pleasant body odor, and adults around 55 who took blackcurrant polyphenols for 7 days had over 25% less 2-nonenal. There are no long-term trials, so combine diet with washing and fabric care.

How can I tell my husband about his body odor without hurting his feelings?

Talk when you are alone together. Start with the chemistry of age that affects both men and women, use “we” or “I” sentences, and suggest changing laundry or bathroom routines together. Focus on what can be done rather than how strong the odor is, and do not tease or tell other people.

Which body or breath odors mean I should see a doctor?

Fruity breath with vomiting, deep rapid breathing or drowsiness needs emergency care right away. Musty-sweet breath with yellow skin, or ammonia breath with swelling and little urine, needs a prompt doctor visit. A persistent fishy odor, a fast change in odor, or heavy sweating with weight loss should be checked within 1–2 weeks.

Scientific mechanism

From fat to odor: omega-7 fatty acids such as palmitoleic acid have a double bond at the seventh carbon from the tail end. When lipid peroxides start an oxidative chain reaction,
the molecule splits at the double bond, giving a 9-carbon unsaturated aldehyde, 2-nonenal, which is volatile and smells greasy and grassy
(Haze 2001).

Why it clings to fabric: 2-nonenal and its parent fats dissolve better in oil than in water, so they stay in skin oil and fabric fibers, especially synthetics. Warm water and surfactants help pull the fats out of fibers
(Abney 2021).

Hormones and raw material: androgens stimulate the oil glands, so men maintain sebum output longer, while women’s output falls after menopause
(Pochi 1979).

Disease odors: when the body burns a lot of fat during insulin deficiency it makes ketones, including acetone, which leave through the breath; a failing liver clears sulfur compounds less well; and failing kidneys let ammonia build up
(Shirasu 2011).

Written and reviewed by Asst. Prof. Dr. Norawit Raatpiboon

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