Pheromones are body scents that we cannot smell. Everyone has over 3 million sweat glands on their skin that are able to put out pheromones. Although we are not consciously aware of them, there is evidence that pheromones from other people affect our behaviour, our feelings about the other person and even the physiology of our bodies. For example, pheromones would explain why women who live together are likely to menstruate at the same time.
Lots of experiments (such as the following examples) suggest that some pheromones convey a sexual message to other people – such as ‘I am available’ or ‘I am attracted to you’ – or help women to spot a man whose immune system would be the best match for her own if she became pregnant by him.
- Researchers asked women to rate some photos of men for attractiveness. When secretly exposed to men’s sweat chemicals, the women rated the men as more attractive – especially the ugly men. Unknowingly, the women may have been responding to pheromone chemicals in the sweat.
- In a different experiment, researchers asked men to smell T-shirts worn by young women, and to rate them for attractiveness of the smell. A T-shirt worn by a woman during her fertile phase of the menstrual cycle was rated as more pleasant and sexy than a T-shirt worn by the same woman during her non–fertile phase. So maybe women have a pheromone that reveals when they are fertile (Proceedings of the Royal Society, May 2001).
- In another experiment, women were asked to smell samples of male sweat, and their brain activity was monitored. Some samples came from men who were being shown sexy images, and when the women smelt these samples special areas of their brains lit up. So it seems that women can probably pick up whether a man is interested in her by the smell of his sweat (Journal of Neuroscience 2008;28:14416–14421).
What Are the Chemicals in Pheromones?
Researchers have not yet managed to identify the actual chemicals that would produce instant sex appeal although, in the USA, products claiming to contain copies of human male and female pheromones are marketed as sexual attractants.
How Do We Smell Pheromones?
A few scientists think we smell pheromones with two tiny pits in the nose known as ‘vomeronasal organs’ (VNOs). (Sometimes they are called ‘Jacobson’s organ, because a Danish doctor called Jacobson first noticed them in the early 1800s.) They suggest that the VNOs have a direct connection to an older, more primal, part of the brain than the area that processes normal smells.
Most scientists argue that the pits in the nose have no function at all in humans and are just leftovers from the dinosaur age. They say that we detect pheromones in the same way that we smell ordinary smells.
First published on: embarrassingproblems.com
Reviewed and edited by: Fiona Elliott
Last updated: December 2020