Ever wondered why a long day or a rigorous workout session leaves you with a not-so-pleasant scent?

Body odour has scientific roots that go beyond mere sweat. It’s a complex interplay between biology, chemistry, and lifestyle factors.

The science of sweat and scent

Our bodies have two main types of sweat glands: eccrine and apocrine. Eccrine glands, found all over the body, help regulate body temperature by releasing saltwater. This type of sweat is usually odourless. On the other hand, apocrine glands, located in areas like the armpits and groin, secrete a thicker fluid rich in proteins and lipids. It’s the interaction of this sweat with the bacteria on our skin that leads to body odour.

Bacteria

The skin’s surface is home to a diverse community of bacteria. When apocrine sweat is released, these bacteria break down the sweat’s proteins and fats, producing compounds with strong, often unpleasant smells. This process is natural and varies greatly from person to person due to differences in skin microbiome composition, diet, health, and hygiene practices.

Factors influencing body odour

Here are some factors that cause body odour:

Genetics and diet

Genetic factors play a significant role in determining body odour. They can influence the composition of sweat, the skin’s microbiome, and even how certain foods are metabolised. Speaking of foods, what we eat can also affect our scent. For instance, consuming large amounts of garlic, onions, or spices can produce a more pungent body odour.

Hormonal changes

Hormonal fluctuations, particularly during puberty, menstruation, pregnancy, or menopause, can intensify body odour. These changes affect sweat gland activity and the composition of sweat, altering the body’s natural scent.

Health and hygiene

Illnesses can influence body odour, as can personal hygiene practices. Regular bathing and wearing clean clothes are essential in managing body odour, as they help remove sweat and reduce the skin bacteria responsible for its breakdown.

Combating body odour: tips and tricks

While body odour is a natural phenomenon, there are ways to manage it effectively:

Maintain good hygiene: Regular washing with soap and water, especially in areas with apocrine glands, can significantly reduce body odour.

Use antiperspirants and deodorants: Antiperspirants help reduce sweating, while deodorants mask or eliminate the odour.

Mind your diet: Be aware of how certain foods may affect your body’s scent.

Stay hydrated: Drinking plenty of water helps flush out toxins that can contribute to body odour.

Wear breathable fabrics: Natural fibres like cotton allow your skin to breathe, reducing sweat accumulation.

This content was created with the help of an AI model and verified by the writer.

We all have colleagues, classmates, neighbours, and friends who emit unpleasant body odours.

If you’re in regular contact with such a person, it can be tricky to convey this, but here’s a gentle way to do it:

Choose a private setting

When addressing someone’s body odour, avoid doing it in front of others, even if you are all friends. If you address them in front of others, it will be seen as an attack or ridicule. Take them aside and express that you have something to discuss.

Start with positivity

Soften the message by framing it within a caring context. Begin by acknowledging their positive qualities. Say, “You’re an amazing person, and I appreciate this and that about you. However, I’ve noticed a change in your body odour, and you don’t smell quite good.”

Gift hygiene items

Instead of an awkward conversation, give them deodorant, mouthwash, or perfume as gifts. They might pick up on the hint. If questioned, mention you had extra during grocery shopping and thought of sharing.

Casually share hygiene tips

Initiate a conversation about good hygiene by saying things like, “Did you know not scraping your tongue can cause bad breath?” or “Wearing a sweaty shirt again isn’t advisable” or “I have a friend selling affordable perfumes” or “Leaving clothes in the sun helps prevent damp odours”

Remember, approaching someone about their body odour requires care and consideration.

Scientists have been using armpit sweat in their experiments.

Their hunch is the smell activates brain pathways linked to emotions, offering a calming effect – but it is far too soon to say if they are right.

They are presenting some of their early findings at a medical conference in Paris this week.

Why and how do we smell?

Babies are born with a strong sense of smell, with a preference for their mother and her breast milk.

Smell helps us humans sense danger – from food or a smoky fire, for example – and interact with our environment, as well as each other.

It also makes meals more tasty and can evoke strong memories too.

Aromas are detected by receptors in the upper part of the nose. Signals from these are then relayed directly to the limbic system, a brain region that is associated with memory and emotions.

The Swedish researchers suggest that human body odour might communicate our emotional state – happy or anxious, for instance – and even elicit similar responses in others who smell it.

They asked volunteers to donate armpit sweat from when they were watching either a scary movie or a happy one.

Next, 48 women with social anxiety agreed to sniff some of these samples, alongside receiving a more conventional therapy called mindfulness, where people are encouraged to focus on the here and now rather than replaying negative thoughts.

Some of the women were given genuine body odour to sniff, while others – the control group – were given clean air instead.

Those who were exposed to the sweat appeared to do better with the therapy.

Lead researcher Ms Elisa Vigna, of the Karolinska Institute in Stockholm, said: “Sweat produced while someone was happy had the same effect as someone who had been scared by a movie clip. So there may be something about human chemo-signals in sweat generally which affects the response to treatment.

“It may be that simply being exposed to the presence of someone else has this effect, but we need to confirm this. In fact, that is what we are testing now in a follow-up study with a similar design, but where we are also including sweat from individuals watching emotionally neutral documentaries.”

What is sweat and does it always smell?

Most of the skin’s sweat is odourless. But sweat glands in the armpit and groin produce certain compounds that cause body odour.

Bacteria on the skin’s surface and on nearby hair follicles break down these compounds, producing others which are responsible for the smell.

Duncan Boak from the charity Fifth Sense, which aims to raise awareness about smell and taste disorders, said: “We know there’s a strong link between our sense of smell and our emotional wellbeing.

“Losing the ability to smell other people, such as your partner and children can cause depression and feelings of isolation.

“Whilst this is a preliminary study and further work is of course needed, it’s very encouraging to see further research around the importance of our sense of smell to good mental health.”

Researchers found out that two dogs carefully sniff each other before deciding whether to play or bark viciously.

They say the sense of smell plays a major role in social interactions and wanted to find out why humans don’t sniff each other before associating with each other like all other mammals do.

The new study was conducted by experts at the Weizmann Institute of Science in Rehovot, Israel and published in the journal Science Advances. 

‘Because humans seek friends who are similar to themselves, we hypothesised that humans may smell themselves and others to subconsciously estimate body odour similarity, which, in turn, may promote friendship,’ the authors say. 

‘Perfect strangers may begin to interest us at first sniffs rather than at first sight alone.’ 

It’s already known that people tend to become friends with others who are similar to themselves in appearance, background, values and even in measures such as brain activity, past studies suggest.