What Your Body’s Natural Smell Could Reveal About Your Health

Body odour is usually treated as something embarrassing, inconvenient, or simply unpleasant. We shower, use deodorant, change clothes, and try not to think too much about it. Yet the smell produced by our bodies is more complicated than it may seem. In some circumstances, changes in body odour can reflect changes happening inside the body.

That does not mean every unusual smell is a warning sign. Diet, exercise, stress, hormones, medication, genetics, and the natural bacteria living on our skin can all influence how we smell. However, persistent or dramatic changes in scent can sometimes be worth paying attention to.

Why does the body smell?

Sweat itself is not necessarily responsible for the strong odour we associate with perspiration. Much of the smell develops when substances produced by our sweat glands interact with microorganisms living on the skin.

The body has several types of sweat glands. Eccrine glands are found across much of the skin and mainly produce a watery mixture containing substances such as water and salt. This type of sweat generally has little smell by itself.

Apocrine glands work somewhat differently. They are concentrated in areas such as the armpits and groin and release a thicker secretion containing proteins and other compounds. On its own, this secretion is relatively low in odour. Once skin bacteria break down these substances, however, they can produce the familiar smells associated with body odour.

This is one reason why two people can sweat a similar amount but smell completely different. Their skin microbiomes, which are the communities of microorganisms living on their skin, may differ significantly.

When could smell be connected to health?

Certain changes in body or breath odour have been associated with medical conditions. One example is diabetes.

When diabetes is poorly controlled, the body may not have enough usable insulin to process glucose effectively. In some situations, it begins breaking down fat, producing chemicals called ketones. A significant build-up of ketones can lead to diabetic ketoacidosis, a potentially life-threatening condition.

One possible sign is a sweet or fruity smell on the breath, sometimes compared with pear drops or nail-polish remover. This should not be ignored, particularly when it occurs alongside symptoms such as excessive thirst, frequent urination, nausea, vomiting, abdominal pain, weakness, or confusion. Suspected diabetic ketoacidosis requires urgent medical attention.

Changes in odour have also been associated with liver and kidney problems. Severe liver disease can sometimes produce a distinctive musty smell, while people with significant kidney dysfunction may develop an ammonia-like odour because the body is less able to remove certain waste products.

It is important to remember that smell alone cannot diagnose these conditions. A person should not assume they have a particular disease simply because their breath or skin smells different.

Could infections change your smell?

Yes. Infections can alter the chemicals produced around affected areas of the body and can therefore change their smell.

A sudden, unusual, or particularly unpleasant odour from a specific part of the body may sometimes occur alongside an infection, especially if there are other symptoms such as redness, swelling, warmth, pain, discharge, or fever.

Changes in smell can also occur because of shifts in the skin microbiome. The balance of microorganisms on our skin is influenced by factors including hygiene, environment, sweat, clothing, hormones, and general health.

Hormones can play a role

Our scent is not necessarily constant throughout life. Hormonal changes can influence sweating and the composition of skin secretions.

Pregnancy, menstruation, puberty, and menopause can all be accompanied by changes in sweating and body odour. These changes do not automatically indicate a health problem. In many cases, they are simply part of normal physiological changes.

Stress can also affect how we smell. Emotional stress activates particular sweat glands and can change the composition of sweat. When bacteria interact with these secretions, the resulting odour may be stronger or noticeably different from the smell produced during ordinary physical activity.

Food, medication, and lifestyle matter too

Before assuming that a new smell signals illness, it is worth considering recent changes in diet or lifestyle.

Foods containing strong-smelling compounds can influence body odour because some of their chemical components or their breakdown products can eventually be released through sweat or breath. Garlic and onions are familiar examples, while strongly spiced foods can have similar effects.

Alcohol and caffeine may also influence sweating and body chemistry. Certain medicines can alter body odour as well.

Exercise is another obvious factor. Sweating more creates greater opportunities for skin bacteria to interact with sweat and produce odour. Clothing can also make a difference, particularly when moisture becomes trapped against the skin.

Genetics are important too. People naturally differ in the amount and composition of their sweat, as well as in the microorganisms that live on their skin. Consequently, having stronger natural body odour than another person does not necessarily mean something is wrong.

Can scientists use smell to detect disease?

Perhaps one of the most interesting areas of research involves the possibility of using human odour as a medical signal.

Scientists are investigating volatile organic compounds, commonly known as VOCs, which are chemicals released by the body. Changes in these compounds may occur in association with certain diseases.

Research has explored whether chemical changes in skin odour could eventually help identify illnesses at an earlier stage. Parkinson's disease has attracted particular interest in this area. Researchers have investigated whether people with the condition produce different chemical profiles that could potentially be detected before more obvious symptoms develop.

There have even been reports of individuals noticing unusual smells associated with relatives before a diagnosis. Such observations are intriguing and have helped inspire scientific research, but they are not currently a substitute for medical testing.

The long-term goal is not necessarily to have doctors simply smell a patient. Instead, researchers are exploring technologies that could analyse complex mixtures of chemicals and identify patterns associated with particular diseases.

What should you do about unusual body odour?

Good hygiene remains one of the simplest ways to manage ordinary body odour. Washing regularly, particularly around areas with many apocrine glands, can reduce the amount of bacteria available to break down sweat.

Antiperspirants can reduce sweating, while deodorants are designed primarily to control or mask odour. Breathable clothing can also help reduce moisture accumulation, particularly during exercise.

However, a persistent and unexplained change deserves more attention than an ordinary episode of sweating.

If your body odour suddenly changes and the change continues despite normal hygiene, consider whether you have recently changed your diet, medication, exercise routine, or other aspects of your lifestyle. If there is no obvious explanation, or if the change occurs alongside other symptoms, speaking with a healthcare professional is sensible.

This is especially important when an unusual fruity, ammonia-like, or otherwise distinctive smell occurs alongside symptoms associated with diabetes, kidney problems, liver disease, or infection.

Your body is constantly communicating

Body odour is not a perfect diagnostic tool, but it is part of the complex chemistry of the human body. What we eat, how much we sweat, the bacteria living on our skin, our hormones, our genes, and our overall health can all contribute to our individual scent.

Scientists are increasingly interested in these chemical signals because they may eventually provide new ways of detecting disease. For now, however, an unusual smell should be treated as a possible clue rather than a diagnosis.

If a change is persistent, unexplained, or accompanied by other concerning symptoms, medical advice is the safest way to find out what is really happening.

Source

BBC Science Focus, published 1 April 2026.

Disclaimer

This article is intended for general informational and educational purposes only. It is not medical advice and should not be used to diagnose, treat, or rule out a medical condition. Body odour can vary naturally for many reasons, and an unusual smell does not necessarily indicate illness. If you experience a persistent or unexplained change in body odour, particularly alongside other symptoms, consult a qualified healthcare professional.