Oh no, you don't want to smell that

What is body odour?

Body odour refers to the collection of scents the human body emits through the skin. These are individual scent patterns that vary from person to person and are shaped by numerous internal factors. Odours can differ depending on the body area, time of day or external influences such as clothing and climate. They are closely linked to biological processes.

Body odour is most noticeable in regions such as the armpits, the feet, the groin or the back. These areas contain many glands that naturally release substances contributing to personal scent. Differences between sexes, age groups and life stages also play a part.

How does body odour develop?

The development of body odour is the result of several interrelated processes occurring mainly on the skin surface. Certain skin glands and the skin's natural microflora play a central role.

The so-called eccrine glands secrete a clear, watery substance that primarily serves to regulate temperature. Other gland types, especially those in hairy regions like the armpits, produce a richer, more complex secretion. This thicker substance contains organic components that serve as an excellent nutrient source for microorganisms.

Countless bacteria live on the skin’s surface and multiply particularly well in warm, moist areas. These microorganisms use substances contained in skin secretions, such as proteins or fats, as an energy source. Their breakdown produces various volatile compounds that are released into the environment and perceived as a specific personal odour.

This effect is particularly pronounced in places where heat and moisture accumulate, for example in tight shoes, under synthetic clothing or beneath the arms. The conditions there favour both gland activity and microbial growth. Depending on an individual's skin flora and secretion composition, both intensity and type of odour can vary considerably.

What causes unpleasant sweat odour?

Under certain circumstances, sweat can smell much stronger or more unpleasant. A common trigger is increased sweating, for example during physical exertion, at high temperatures or under emotional stress. If sweat does not evaporate or is not removed quickly, but becomes trapped in non-breathable clothing or on poorly ventilated skin areas, a warm, damp environment can form that promotes specific skin reactions.

Dietary habits also influence the perception of one’s sweat odour. Strongly spiced foods, alcohol or garlic can lead to breakdown products being excreted through the skin. Such changes are usually temporary but noticeable. A fresh, plant-based diet can have a generally positive effect on personal scent.

Certain life stages such as puberty or cycle-related fluctuations can lead to differences in the type or intensity of body odour. In addition, the intake of certain medications can play a role. They may affect metabolism, which in turn alters the composition of excretions and the perceived scent note.

Why does sweat smell like onions?

An onion-like smell in sweat is often very unpleasant for those affected but harmless and explainable. It occurs when bacteria living on the skin break down certain components of sweat – especially sulphur-containing compounds. This produces volatile substances called thiols, which smell like onions or garlic.

This scent is particularly noticeable in women, because their sweat contains, due to hormonal factors, more sulphur compounds. Men, on the other hand, usually develop a more cheesy to pungent body odour. This is due to the breakdown of testosterone.

Diet also plays an important role: people who regularly eat onion- or garlic-containing dishes excrete their essential oils through sweat – with a clearly noticeable result.

Besides harmless triggers such as food and hormones, infections or health disorders can also be involved. An onion-like smell in the intimate area may indicate a disturbed vaginal flora or a fungal infection and should be checked by a doctor. A sudden change in sweat odour can, in individual cases, be a sign of hormonal or metabolic disease.

Sweat smells like urine: why does this happen?

An unpleasant, urine-like sweat odour should not be ignored, as it can indicate serious processes in the body. Ammonia is often the cause: when metabolic waste products are not eliminated via the kidneys as usual, they enter the bloodstream and are excreted through the skin or breath. This can happen particularly in advanced kidney disease. The kidneys then no longer filter toxins sufficiently, causing them to accumulate and produce noticeable body odours – especially under the armpits, but also on the trunk, in the intimate area or on hands and feet.

Dietary style is another important factor. Following a very low-carbohydrate diet (e.g. a no-carb diet) or training intensively forces the body to obtain energy from proteins. Ammonia forms as a by-product and is excreted through sweat, causing the urine-like smell. In addition, medications can be triggers. Some preparations, such as certain antiepileptics or products containing hydrocortisone, can raise ammonia levels in the body and thus change body odour.

In some cases, altered body odour can also point to liver overload. If detoxification function is impaired, toxins may also be excreted via the skin. If additional symptoms such as chronic fatigue, high blood pressure, shortness of breath, fluid retention or nausea occur, it is strongly advisable to consult a doctor.

How to effectively reduce body odour: useful tips

• Shower regularly, but sensibly. Generally, washing daily with lukewarm water and mild soap is sufficient. Too frequent showers, especially with hot water, can damage the skin's acid mantle and even increase sweat production.
• Shave your armpits to reduce bacterial load. Hair retains moisture and provides an ideal nutrient base for bacteria – smooth skin stays drier and more hygienic.
• Use an antiperspirant that works, rather than one that only smells pleasant. When buying, look for the label “Antiperspirant”. Unlike simple deodorants that only mask unpleasant body odours, these products actively inhibit sweat production.
• Also wear breathable clothing made of natural materials. Cotton, linen and merino wool absorb moisture better and allow air to circulate. This prevents heat build-up under clothing.
• Avoid synthetic fibres, especially during sport and in heat. Polyester and similar fabrics trap sweat, promote unpleasant odours and dry less well – particularly in sensitive body areas.
• Wash clothing immediately after wearing. Especially underwear, T-shirts and tight garments should not be put back in the wardrobe but washed right away, otherwise odour-causing bacteria can form.
• Pre-treat clothing with sweat odour specifically. You can use a mixture of vinegar and lukewarm water in a 4:1 ratio to soak textiles. Then wash clothing at a high temperature to remove even deeply embedded sweat smells.
• If necessary, you can store washed clothing in the freezer. Freezing them in airtight bags overnight kills bacteria. This is ideal for garments that still smell after washing.
• Drink enough water throughout the day. When dehydrated, sweat becomes more concentrated and therefore smells stronger. At least 1.5 to 2 litres daily help reduce odours and stabilise circulation.
• Watch your diet if you have strong body odour. Foods such as garlic-containing dishes, curry, onions, red meat and chili affect sweat odour – often for days afterward.
• Incorporate odour-neutralising foods into your routine. Eat citrus fruits, parsley, basil, apples or drink green tea. These foods have a positive effect on personal scent as they regulate from within.
• Support your gut flora with probiotic foods. A healthy gut can reduce unpleasant bodily emissions. Yogurt, kefir or fermented vegetables support balance in the digestive system.
• To rule out bromhidrosis or diseases of the apocrine glands, noticeable armpit odour, bad breath or unusual breath should be medically examined. Often an androstenone-related problem is involved.
• Use essential oils like rosemary or lemon in a targeted way. Rosemary oil is antibacterial and refreshes the skin. Whether as a bath additive or dabbed onto the armpits: it gently and effectively reduces body odour.

Sometimes the body says more than words – also through its personal scent. Those who are attentive can recognise these signals early and act accordingly.