Reproductive hormones related to a woman's attractiveness

The reproductive hormones control the monthly cycle of the woman and regulate the fertility. Reproductive hormones are also linked to the attractiveness of a woman for a study. Researchers at the University of Bern have shown that some women feel better about men than others, namely those who are most "fit" for reproduction.

We do not just trust our eyes but we also follow our nose: it 's not only the visual impression that plays an important role in the choice of a partner, but also its smell, both in the animal kingdom and in man. Previous studies have shown that a woman's sense of smell changes in the course of the menstrual cycle: a woman feels the most attractive to the male nose during the most fertile days, during the period when she can actually reproduce. What remained unanswered until now: do some women feel "better" than others?

A team of researchers led by Daria Knoch of the Department of Social Psychology and Social Neuroscience at the University of Bern, in collaboration with colleagues from the University of Konstanz, Thurgauer Institute of Economics and the Hospital University of Bern, is really the case: the perfume of some women is universally more attractive for men than for others.

The reproductive hormones make the feminine scent attractive

Researchers have also discovered the reason for this: women are perceived as being more or less attractive by men based on their hormone levels. "Women with high levels of estrogen and low progesterone are the most attractive to men in an olfactory sense," says Daria Knoch. This has no doubt a meaning in an evolutionist perspective. These hormone levels, many estrogens and little progesterone, indicate high female fertility. According to the theory of evolution, men are looking for women with whom they can reproduce.

The researchers also investigated other factors that may influence body odor: the stress hormone called cortisol and some genes that impact the immune system. "Several studies postulate that the choice of a partner is based on the fact that men and women have a different immune system so that children can defend themselves from birth against pathogens," says lead author Janek Lobmaier of Social Psychology and Social Neuroscience. Department at the University of Bern. But the results clearly show that these two factors have no influence on the appeal of the female perfume.

Strict test protocol

The researchers conducted their study with 28 women and 57 men. Women who donated their body odor followed "a strict protocol to minimize the factors that could distort odors," says Lobmaier. Women were not allowed to use hormonal contraception, to abstain from sex while collecting odors, to wash themselves and their clothes with neutral detergents, do not drink alcohol or eat spicy foods these days. During the peak fertility period, they stuck cotton pads overnight to "capture" their unique body odor. Their hormone levels were determined with the help of saliva samples. Later, men sniffed cotton swabs at the lab and assigned each scent 0 to 100 points – with the result known.

"Reproductive hormones are indicators of a woman's fertility, and the higher the level, the more attractive the woman is to men," says Lobmaier. Estrogen, for example, also has a positive effect on the visual appeal of a woman, as studies show: High levels of estrogens make the face and body of 39, an attractive woman for men. And their smell too, with women who do not use any hormonal contraception. The study did not study how the pill affects this. "However, it is presumed that hormonal contraception can distort the body's odor," says Knoch. The study was published in Acts of the Royal Society B newspaper.

Explore more:
How does overweight affect fertility?

More information:
Janek S. Lobmaier et al. The smell of attractiveness: reproductive hormone levels account for individual differences in women's body odor, Acts of Royal Society B: Biological Sciences (2018). DOI: 10.1098 / rspb.2018.1520