Human sex pheromones

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No study has led to the isolation of true human sex pheromones, although various researchers have investigated the possibility of their existence. [1] [2]

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Pheromones, in general, are secreted chemical substances by organisms that trigger a social reaction in the same species. Sex pheromones are a special type of olfactory signal, produced to attract the opposite sex, to encourage mating or to perform some other function closely related to sexual reproduction. While humans are highly dependent upon visual cues, smells can also play a role in sociosexual behaviors. An inherent difficulty in studying human pheromones is the need for cleanliness and odorlessness in human participants. [3]

Experiments have focused on three classes of putative human sex pheromones: axillary steroids, vaginal aliphatic acids and stimulators of the vomeronasal organ.

Axillary steroids are produced by the testicles, ovaries, apocrine glands and adrenal glands. [4] These chemicals are not biologically active until puberty when sex steroids influence their activity. [5] The activity change during puberty suggests that humans communicate through odors. [4] Several axillary steroids have been described as possible human pheromones: androstadienol, androstadienone, androstenone, androstenol, and androsterone.

Androstenol is the putative female pheromone. [5] In a 1978 study by Kirk-Smith, people wearing surgical masks treated with androstenol or untreated were shown pictures of people, animals and buildings and asked to rate their attractiveness. [6] Individuals with their masks treated with androstenol rated their photographs as being "warmer" and "more friendly". [6] The best-known case study involves the synchronization of menstrual cycles among women based on unconscious odor cues, the McClintock effect , named after the primary investigator, Martha McClintock, of the University of Chicago. [7] [8] A group of women were exposed to a whiff of perspiration from other women. Depending on the time in the month the sweat was collected (before, during, or after ovulation), there was an association with the recipient woman's menstrual cycle to speed up or slow down. The 1971 study proposed two types of pheromones involved: "One, produced prior to ovulation, shortens the ovarian cycle; and the second, produced just at ovulation, lengthens the cycle". However, recent studies and reviews of the methodology have called the validity of her results into question. [9] [10] A 2013 meta-review of existing studies showed that the syncing of ovarian cycles likely did not exist. [11]

Androstenone is postulated to be secreted only by men as an attractant for women and is also thought to affect their mood positively. It seems to have different effects on women, depending on where a female is in her menstrual cycle, with the highest sensitivity to it during ovulation. [5] In 1983, study participants exposed to androstenone were shown to undergo changes in skin conductance. [12] Androstenone has been found to be perceived as more pleasant to women at a woman's time of ovulation. It is hypothesized that this may be a way for a male to detect an ovulating female who would be more willing to be involved in sexual interaction. [1] [2] [3] [13]

See also

Related Research Articles

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Estrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal activity: estrone (E1), estradiol (E2), and estriol (E3). Estradiol, an estrane, is the most potent and prevalent. Another estrogen called estetrol (E4) is produced only during pregnancy.

<span class="mw-page-title-main">Menstruation</span> Shedding of the uterine lining

Menstruation is the regular discharge of blood and mucosal tissue from the inner lining of the uterus through the vagina. The menstrual cycle is characterized by the rise and fall of hormones. Menstruation is triggered by falling progesterone levels, and is a sign that pregnancy has not occurred.

<span class="mw-page-title-main">Pheromone</span> Secreted or excreted chemical factor that triggers a social response in members of the same species

A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavior of the receiving individuals. There are alarm pheromones, food trail pheromones, sex pheromones, and many others that affect behavior or physiology. Pheromones are used by many organisms, from basic unicellular prokaryotes to complex multicellular eukaryotes. Their use among insects has been particularly well documented. In addition, some vertebrates, plants and ciliates communicate by using pheromones. The ecological functions and evolution of pheromones are a major topic of research in the field of chemical ecology.

<span class="mw-page-title-main">Ovulation</span> Release of egg cells from the ovaries

Ovulation is an important part of the menstrual cycle in female vertebrates where the egg cells are released from the ovaries as part of the ovarian cycle. In female humans ovulation typically occurs near the midpoint in the menstrual cycle and after the follicular phase. Ovulation is stimulated by an increase in luteinizing hormone (LH). The ovarian follicles rupture and release the secondary oocyte ovarian cells.

<span class="mw-page-title-main">Sexual attraction</span> Attraction on the basis of sexual desire

Sexual attraction is attraction on the basis of sexual desire or the quality of arousing such interest. Sexual attractiveness or sex appeal is an individual's ability to attract other people sexually, and is a factor in sexual selection or mate choice. The attraction can be to the physical or other qualities or traits of a person, or to such qualities in the context where they appear. The attraction may be to a person's aesthetics, movements, voice, among other things. The attraction may be enhanced by a person's body odor, sex pheromones, adornments, clothing, perfume or hair style. It can be influenced by individual genetic, psychological, or cultural factors, or to other, more amorphous qualities. Sexual attraction is also a response to another person that depends on a combination of the person possessing the traits and on the criteria of the person who is attracted.

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<span class="mw-page-title-main">Concealed ovulation</span> Lack of visible changes in ovulating females

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<span class="mw-page-title-main">Androstenone</span> Chemical compound

Androstenone (5α-androst-16-en-3-one) is a 16-androstene class steroidal pheromone. It is found in boar's saliva, celery cytoplasm, and truffle fungus. Androstenone was the first mammalian pheromone to be identified. It is found in high concentrations in the saliva of male pigs, and, when inhaled by a female pig that is in heat, results in the female assuming the mating stance. Androstenone is the active ingredient in 'Boarmate', a commercial product made by DuPont sold to pig farmers to test sows for timing of artificial insemination.

Menstrual synchrony, also called the McClintock effect, or the Wellesley effect, is a contested process whereby women who begin living together in close proximity would experience their menstrual cycle onsets becoming more synchronized together in time than when previously living apart. "For example, the distribution of onsets of seven female lifeguards was scattered at the beginning of the summer, but after 3 months spent together, the onset of all seven cycles fell within a 4-day period."

<span class="mw-page-title-main">Androstenol</span> Mammalian pheromone also found in truffles

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<span class="mw-page-title-main">Estratetraenol</span> Chemical compound

Estratetraenol, also known as estra-1,3,5(10),16-tetraen-3-ol, is an endogenous steroid found in women that has been described as having pheromone-like activities in primates, including humans. Estratetraenol is synthesized from androstadienone by aromatase likely in the ovaries, and is related to the estrogen sex hormones, yet has no known estrogenic effects. It was first identified from the urine of pregnant women.

<span class="mw-page-title-main">Androstadienone</span> Chemical compound

Androstadienone, or androsta-4,16-dien-3-one, is a 16-androstene class endogenous steroid that has been described as having potent pheromone-like activities in humans. The compound is synthesized from androstadienol by 3β-hydroxysteroid dehydrogenase, and can be converted into androstenone by 5α-reductase, which can subsequently be converted into 3α-androstenol or 3β-androstenol by 3-ketosteroid reductase.

Odour is sensory stimulation of the olfactory membrane of the nose by a group of molecules. Certain body odours are connected to human sexual attraction. Humans can make use of body odour subconsciously to identify whether a potential mate will pass on favourable traits to their offspring. Body odour may provide significant cues about the genetic quality, health and reproductive success of a potential mate.

<span class="mw-page-title-main">Fertility testing</span> Process for assessing human fertility

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<span class="mw-page-title-main">Androstadienol</span> Chemical compound

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<span class="mw-page-title-main">Fasedienol</span> Chemical compound

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<span class="mw-page-title-main">16-Androstene</span>

16-Androstenes, or androst-16-enes, are a class of endogenous androstane steroids that includes androstadienol, androstadienone, androstenone, and androstenol, which are pheromones. Some of the 16-androstenes, such as androstenone and androstenol, are odorous, and have been confirmed to contribute to human malodor.

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References

  1. 1 2 Wysocki, Charles J.; Preti, George (7 October 2004). "Facts, fallacies, fears, and frustrations with human pheromones". The Anatomical Record. 281A (1): 1201–1211. doi: 10.1002/ar.a.20125 . PMID   15470677. It is emphasized that no bioassay-guided study has led to the isolation of true human pheromones, a step that will elucidate specific functions to human chemical signals.
  2. 1 2 Riley, Alex (9 May 2016). "Pheromones are probably not why people find you attractive". BBC News. Retrieved 2016-05-09.
  3. 1 2 Grammer, Karl; Fink, Bernhard; Neave, Nick (2005). "Human pheromones and sexual attraction". European Journal of Obstetrics and Gynecology and Reproductive Biology. 118 (2): 135–142. doi:10.1016/j.ejogrb.2004.08.010. PMID   15653193.
  4. 1 2 Hays, Warren S. T. (2003). "Human pheromones: have they been demonstrated?". Behavioral Ecology and Sociobiology. 54 (2): 89–97. Bibcode:2003BEcoS..54...89H. doi:10.1007/s00265-003-0613-4. JSTOR   25063239. S2CID   37400635.
  5. 1 2 3 Mostafa, Taymour; Khouly, Ghada El; Hassan, Ashraf (2012). "Pheromones in sex and reproduction: Do they have a role in humans?". Journal of Advanced Research. 3 (1): 1–9. doi: 10.1016/j.jare.2011.03.003 .
  6. 1 2 Kirk-Smith, Michael (1978). "Human social attitudes affected by androstenol". Research Communications in Psychology, Psychiatry & Behavior. 3 (4): 379–384. ISSN   0362-2428.
  7. ↑ McClintock, M.K. (January 1971). "Menstrual synchrony and suppression". Nature. 229 (5282): 244–5. Bibcode:1971Natur.229..244M. doi:10.1038/229244a0. PMID   4994256. S2CID   4267390.
  8. ↑ Stern, K., McClintock. M.K. (March 1998). "Regulation of ovulation by human pheromones". Nature. 392 (6672): 177–9. Bibcode:1998Natur.392..177S. doi:10.1038/32408. PMID   9515961. S2CID   4426700.{{cite journal}}: CS1 maint: multiple names: authors list (link).
  9. ↑ Yang, Zhengwei; Schank, Jeffrey C. (2006). "Women Do Not Synchronize Their Menstrual Cycles". Human Nature. 17 (4): 434–447. doi:10.1007/s12110-006-1005-z. PMID   26181612. S2CID   2316864 . Retrieved 2007-06-25.
  10. ↑ Strassmann BI (March 1999). "Menstrual synchrony pheromones: cause for doubt". Hum. Reprod. 14 (3): 579–80. doi: 10.1093/humrep/14.3.579 . PMID   10221677.
  11. ↑ Harris, Amy L.; Vitzthum, Virginia J. (2013-04-01). "Darwin's Legacy: An Evolutionary View of Women's Reproductive and Sexual Functioning". The Journal of Sex Research. 50 (3–4): 207–246. doi:10.1080/00224499.2012.763085. ISSN   0022-4499. PMID   23480070. S2CID   30229421.
  12. ↑ Toller, C. Van; Kirk-Smith, M.; Wood, N.; Lombard, J.; Dodd, G.H. (1983). "Skin conductance and subjective assessments associated with the odour of 5-α-androstand-3-one". Biological Psychology. 16 (1–2): 85–107. doi:10.1016/0301-0511(83)90056-X. PMID   6682682. S2CID   54325922.
  13. ↑ Stromberg, Joseph (13 March 2015). "How one perfume company misled scientists into believing in human sex pheromones". Vox . Retrieved 23 July 2015. ... But the basic truth is that we have no evidence human pheromones even exist — and these studies can all be traced back to a single fragrance company called Erox that managed to convince dozens of scientists their two 'pheromones' were worth researching in the first place.

Bibliography

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