Can your unique 'smell' — what your body smells like — change naturally? And when would this happen? I thought maybe when you were a baby and maybe puberty, but would it change if you were in love too?
—Lara
If love really does change everything including body odour, women are more likely to sniff it out than men.
Our personal odour is as unique as our DNA — in fact, our 'odour print' is determined partly by a group of genes on the sixth chromosome related to immune function which are known as the major histocompatibility complex.
But while our genetically-founded odour print remains unchanged through our lifetime, our scent has other layers of complexity and people emit different odours as they age.
Anyone who has spent time around active teenage boys will agree that hormonal changes play a big part in the way we smell.
"Diet also influences the way we smell," says Dr Charles Wysocki, a behavioural neuroscientist at Monell Chemical Senses Center in Philadelphia, USA.
Vegetarians smell different to meat-eaters and eating dairy products also affects your body's odour.
Emotional experiences also influence our body odours short-term, with some research showing that subjects who have watched movie clips that made them fearful or anxious have had changes in their body odour that was recognised by other people.
"What we don't know, is whether a person will become anxious or fearful if they smell an individual who is anxious or fearful," Wysocki says.
"Love is another emotional experience. When a person is in love, does the body odour change? That hasn't been tested, but given what is known about changes in body odour, if an individual encounters their loved one, I suspect that their body odour might change," he continues.
But beware, women looking for the man of their dreams should lay off the perfume because it hides their true scent from their ideal genetic partner, according to recent research by Wysocki and colleagues.
However, women are still likely to recognise a potential mate's natural scent through any aftershave or other fragrance that a man might slap on before a hot date.
"We found that using different fragrance materials to reduce the impact of a man's body odour will work on the nose of other men — but won't work on the nose of women," says Wysocki.
"A woman's nose seems to be much more tuned into ... body odours. We can find fragrances that reduce the impact of body odour from women on men," he says.
"We think that, from an evolutionary perspective, that's because women need to gain as much information as possible about potential mates because they have a very limited number of times that they can have successful pregnancies."
Subjects asked to select a prospective date from the smell of a T-shirt they had worn usually preferred the scent of a person whose immune system was genetically quite different to their own, Wysocki says, giving potential offspring optimal protection.
"Whether this goes part way to explaining the chemistry behind physical attraction, we don't know, but it may be going on at the subconscious level."
Dr Charles Wysocki was interviewed by Fran Molloy.
