Copulins

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Copulins were first described in the vaginal secretion of female rhesus monkeys.

Copulins (from Latin copulāre , 'to connect', 'to put together'; see also copulation ) are female sexual odor substances . They were first described in 1971 and represent a group of volatile and short-chain fatty acids that occur in vaginal secretions depending on the cycle . They are believed to be attractive to male primates and would then be among the vertebrate pheromones produced by females .

Discovery and Properties

Illustration of the cycle-dependent copulin production. Data points averaged from 27 cycles with standard errors for copulin-producing women; Reprint of Figure 2 in.

After indications of odorous substances that are critical for sexual attractiveness in primates, copulins were extracted for the first time from the vaginal secretion of rhesus monkeys and, along with steroids (such as androstanol and androstenone ) and vomeropherins , are probably among the most intensively studied pheromone candidates in primates. Important components are acetic acid , propionic acid , butyric acid , isobutyric acid , 2-methylbutyric acid , isocaproic acid and isovaleric acid , all of which are volatile , aliphatic and short-chain carboxylic acids .

Both the absolute amount and the relative proportion of these individual components depend on the hormone level and the phase of the sexual cycle or menstrual cycle (see figure). The highest copulin production is reached around ovulation . The proportion of acetic acid changes little during the cycle, whereas the proportion of isobutyric acid fluctuates strongly. This could be an indication that isobutyric acid plays a particularly important role in communicating the willingness to conceive.

Copulins (like androstenes) are not classic odorous substances. They smell clearly unpleasant in high concentration, but are attractive in lower concentration. The vaginal odor is not caused by copulins, but arises from the combination of more than 2000 different substances, of which copulins make up only a small proportion. Copulins complement male odorous substances, such as androstanol and androstenone, to form an olfactory communication path of higher primates.

After rhesus monkeys, for which the sense of smell plays an essential role in mating behavior, copulins have also been described in humans (see figure), bear macaques and chimpanzees .

Human copulins

Human vaginal secretions are very similar to those of other primates. They contain the same volatile fatty acids, but in a different composition and with substantial individual differences. There is also evidence that oral contraceptives inhibit copulin production in some women .

In men physiological changes and behavioral differences were observed after Kopulinexposition. An increase in testosterone and cortisol levels in saliva has been reported . They value the sexual attractiveness of themselves and women's faces higher than the control group, and their willingness to cooperate with other men decreases.

Some scientists have raised the question of why copulins retained their effects in the evolution of modern humans. The invention of the upright gait and the historically more recent use of clothing would make the use of a semiochemical system more difficult for modern humans than for example for rhesus monkeys. For people, intimate situations are required in order to be able to perceive a woman's genitals olfactory. They go so far as to speculate that cunnilingus might be a suitable sexual practice in which the male partner semiochemically collects information.

Critique of the human copulins

Modern studies, which were conducted blindly against a placebo with large control groups, describe difficulties in reproducing the above-described effects of copulins on men , and even early studies on rhesus monkeys have been scientifically criticized. The original studies may have suffered from a lack of critical discussion, poor statistics and the selective publication of positive results, a so-called confirmation error.

The evidence for copulins as pheromones of primates is significant thinner than classical pheromones as bombykol of the silkworm , tiglic aldehyde in rabbits and 4-ethyloctanal in goats. Scientists like Tristram D. Wyatt from Oxford write that there is still no robust evidence for the effects of human pheromones and copulins. Earlier studies are to be viewed critically and if one were to look seriously for human pheromones, humans would have to be examined like a newly discovered mammal and molecular candidates would have to be constructively identified.

Cultural influences

Even before copulins were first described in 1971, odorous substances were associated with vaginal secretions and it was used because of its allegedly attractive effect.

“Sexual excitement causes all sorts of exotic odors to emanate from the breath, the skin, and in particular the genitalia. [...] Courtesans of medieval Europe used to wear a little of their vaginal secretions as perfume to attract others, dabbing it behind their ears and necks and on their chests. "

“Sexual arousal creates all sorts of exotic smells that are given off by the breath, the skin and especially the genitals. [...] It was customary for courtesans in medieval Europe to wear a small amount of their vaginal secretions as a perfume to attract others. They dabbed the skin behind the ears, neck and chest with it. "

- Linda Louisa Dell : Aphrodisiacs

Copulins were and are produced commercially. The first patent on copulin-inspired perfumes was registered a year after it was first described by its discoverer Richard P. Michael, and synthetic odorous substances, which are supposed to increase the attractiveness of men, have been produced and marketed as perfumes under various names since then. There is little experimental evidence for the effectiveness of such synthetic analogues.

The attempt and anecdotal success to enrich synthetic fragrance mixtures with natural vaginal secretions achieved some media coverage. The spectacular behavior-changing effect of odorous substances was also reflected in the literature, for example in the novel Das Parfum .

Individual evidence

  1. ↑ a b c R. F. Curtis, JA Ballantine, EB Keveren, RW Bonsall, RP Michael: Identification of primate sexual pheromones and the properties of synthetic attractants. In: Nature. Volume 232, Number 5310, August 1971, pp. 396-398, doi: 10.1038 / 232396a0 , PMID 4999879 .
  2. ^ RP Michael, EB Keverne, RW Bonsall: Pheromones: isolation of male sex attractants from a female primate. In: Science. Volume 172, Number 3986, May 1971, pp. 964-966, doi: 10.1126 / science.172.3986.964 , PMID 4995585 .
  3. ↑ a b c d R. P. Michael, RW Bonsall, M. Kutner: Volatile fatty acids, "copulins", in human vaginal secretions. In: Psychoneuroendocrinology. Volume 1, Number 2, 1975, pp. 153-163, doi: 10.1016 / 0306-4530 (75) 90007-4 , PMID 1234654 .
  4. ^ A b R. P. Michael, EB Keverne: Pheromones in the communication of sexual status in primates. In: Nature. Volume 218, Number 5143, May 1968, pp. 746-749, doi: 10.1038 / 218746a0 , PMID 4968116 .
  5. ↑ a b Warren ST Hays: Human pheromones: have they been demonstrated? In: Behavioral Ecology and Sociobiology. Volume 54, Number 2, July 2003, pp. 89-97, doi: 10.1007 / s00265-003-0613-4
  6. ↑ a b c d L. Keith, P. Stromberg, BK Krotoszynski, J. Shah, A. Dravnieks: The odors of the human vagina. In: Archives for Gynacology. Volume 220, Number 1, December 1975, pp. 1-10, doi: 10.1007 / BF00673143 , PMID 1243522 .
  7. ↑ a b c Megan N. Williams, Amy Jacobson: Effect of Copulins on Rating of Female Attractiveness, Mate-Guarding, and Self-Perceived Sexual Desirability. In: Evolutionary Psychology. Volume 14, Number 2, 2016, pp. 1-8, doi: 10.1177 / 1474704916643328
  8. ↑ a b K. Grammer, A. Jütte: The war of fragrances: Importance of pheromones for human reproduction. In: Gynecological Obstetric Rundschschau. Volume 37, 1997 pp. 149-153, online
  9. ↑ JJ Sokolov, RT Harris, MR Hecker: Isolation of substances from human vaginal secretions previously shown to be sex attractant pheromones in higher primates. In: Archives of sexual behavior. Volume 5, Number 4, July 1976, pp. 269-274, doi: 10.1007 / BF01542078 , PMID 986135 .
  10. ↑ a b A. L. Cerda-Molina, L. Hernández-López, CE de la O, R. Chavira-Ramírez, R. Mondragón-Ceballos: Changes in Men's Salivary Testosterone and Cortisol Levels, and in Sexual Desire after Smelling Female Axillary and Vulvar Scents. In: Frontiers in endocrinology. Volume 4, 2013, p. 159, doi: 10.3389 / fendo.2013.00159 , PMID 24194730 , PMC 3809382 (free full text).
  11. ↑ Megan N. Williams, Coren Apicella: Synthetic Copulin Does Not Affect Men's Sexual Behavior. In: Adaptive Human Behavior and Physiology. Volume 11, 2017 doi: 10.1007 / s40750-017-0083-y
  12. ↑ David A. Goldfoot: Olfaction, Sexual Behavior, and the Pheromone Hypothesis in Rhesus Monkeys: A Critique. In: Integrative and Comparative Biology. Volume 21, Number 1, 1981, pp. 153-164, doi: 10.1093 / icb / 21.1.153
  13. ↑ a b T. D. Wyatt: The search for human pheromones: the lost decades and the necessity of returning to first principles. In: Proceedings of the Royal Society B. Biological sciences. Volume 282, number 1804, April 2015, p. 20142994, doi: 10.1098 / rspb.2014.2994 , PMID 25740891 , PMC 4375873 (free full text) (review).
  14. ↑ Linda Louisa Dell: Aphrodisiacs: To AZ . Skyhorse Publishing Company, Incorporated, 2015, ISBN 978-1-63220-481-3 .
  15. ↑ Patent FR2124399 : Compositions olfactives à base d'acides gras et leurs utilisation pharmaceutiques et dans des produits de toilette. Published February 2, 1972 , inventor: RP Michael. ‌
  16. ^ NL McCoy, L. Pitino: Pheromonal influences on sociosexual behavior in young women. In: Physiology & behavior. Volume 75, Number 3, March 2002, pp. 367-375, doi: 10.1016 / S0031-9384 (01) 00675-8 , PMID 11897264 .
  17. ↑ A. Winman: Do perfume additive Termed human pheromones warrant being Termed pheromones? In: Physiology & behavior. Volume 82, Number 4, September 2004, pp. 697-701, doi: 10.1016 / j.physbeh.2004.06.006 , PMID 15327919 .
  18. ↑ Allison Ramirez: I Wore Perfume Made From My Vagina to See if It Would Get Me Better Dates. In: Cosmopolitan . January 30, 2017