Scientists believe they have discovered the reason why mosquitoes find some of us more tasty than others.
Mosquitoes are also attracted by warmth
It was already known that some people produce "come and get me" smells which appeal to the blood-suckers.
Rothamsted Research, in Herts, found those less likely to be bitten produced odours which masked these scents.
The natural repellent could be used to protect everyone from the bugs, suggests the Biotechnology and Biological Sciences Research Council.
Until that happens, people who are frequently bitten might benefit from hanging around those who escape relatively unscathed.
When herds of cattle contain larger numbers of cows that give off masking odours, fewer mosquitoes will bother the herd.
Rothamsted Research tested the behavioural reaction of yellow fever mosquitoes to the odour of a handful of volunteers.
The results identified several compounds that reduced "an attractive person down to a level of attractiveness that is similar to blank air", said team member James Logan.
Other researchers had presumed some people were lacking certain attractive odours.
"What we are saying is these attractants are still there but some people produce extra chemicals which can mask them," he said.
He said it might be possible to make new insect repellents that contain these natural masking odours.
They would likely be completely odourless to humans, unlike current mosquito repellents, he said.
Colleague Professor John Pickett said: "We have identified about 11 compounds. We are going to narrow that down to the most attractive and work out which mixtures of those are the most effective."
Professor Chris Curtis of the London School of Hygiene and Tropical Medicine, said it was true that some people were more attractive to mosquitoes than others, but warmth "is another important factor".
One of his students found that his warm, sweaty jogging socks were particularly alluring to the bugs.