Review Article

Pheromones: Does humans emit scent signals

Shrikant L Patil

Assistant Professor, Department of , K. S. Hegde Medical Academy, Nitte University, Deralakatte, Mangalore-575018, Karnataka, INDIA. Email: [email protected]

Abstract The invisible, colourless chemical scent emitted by human beings is known as , these chemical signalling molecules are volatile, odorous substances, triggering some sort of physiological reaction. The physiological reactions can manifest themselves in a variety of different ways: some pheromones affect , some modulate sexual activity and other pheromones have similarly diverse effects on the target animal. Pheromones have been known to perform main role in number of organisms ranging from amoebas to fish to mammals, including . However, the question of whether does humans emit sex scents signals? Do human olfactory signals for pheromones exist? Has been a question of much debate with few definite conclusions. In this paper I will look at some possible examples of odour signalling in humans. Key Words: Pheromones, vomeronasl organ, sex, odour, behaviour.

Address for Correspondence: Dr. Shrikant L. Patil, Assistant Professor, Department of Physiology, K. S. Hegde Medical Academy, Nitte University, Deralakatte, Mangalore-575018, Karnataka, INDIA. Email: [email protected] Received Date: 09/04/2017 Revised Date: 10/05/2017 Accepted Date: 22/06/2017 DOI: https://doi.org/10.26611/103323

Access this article online remains the same question as to whether humans can also secrets these chemical signalling molecules called as 4-6 Quick Response Code: pheromones . Researchers from Sweden used brain Website: imaging procedures which have found the evidence those www.medpulse.in men and women can in fact release and receive the subconscious odour signals, both of them, responds to 7-10 theses odour signals differently . The airborne chemical messengers released from human body (i.e. urine and Accessed Date:

sweat) are known as human pheromones which haves 28 August 2017 direct impact on physical and emotional changes on

another fellow humans. Most of the animals including

humans can detect, smell these pheormoens with the help INTRODUCTION of half-moon shaped specialized structure located inside Pheromones are chemicals secreted by a particular animal the nose called the vomeronasl organ (VMO). On the which can alters/changes the behaviour of the another other hand, non- scents such as the smell of animal belongs to the same . Many scientists have food or flowers are sensitized by another part of nose described pheromones are one of those behaviour-altering called as olfactory . Pheromonal signals sensed agents, which can trigger different behavioural changes by VMO then relayed through olfactory nerves to apart from the sexual behaviour in the animal belongs to olfactory cortex, then some part of send to an the same species. Pheromones are known as area of the brain called , which is known for ectohormones – i.e. they act outside of the individuals its activity to alter the hormonal changes, , sexual body who secrets them – they alter the behaviour of and reproduction behaviour 11,12 . A Signature Scent: As another individual. In case of which only can the search for human pheromones continues, scientists affect the individuals body functions that secrets them 1-3. have also investigated other potential explanations for the It is well documented that males and females of many subtle effects of smells. Consider, for example, the species can emits or can communicate through chemical finding that human infants will crawl toward the odour of signals (chemotaxis) known as pheromones, but there their mother’s breast. Baby rabbits are known to begin

How to cite this article: Shrikant L Patil. Pheromones: Does humans emit sex scent signals . MedPulse International Journal of Physiology. August 2017; 3(2): 15-18. https://www.medpulse.in/Physiology/ MedPulse International Journal of Physiology, Print ISSN: 2550-7613, Volume 3, Issue 2, August 2017 pp 15-18 nursing when exposed to a specific pheromone from a believe that human behaviours are geneder-specific, this lactating mother rabbit. Yet the human infants might may be because of the way we chemically perceive the simply be attracted to a mother’s so-called odour print, or opposite sex is very different than the way we perceive unique personal scent. Odour prints are influenced by members of the same sex 11,12 . A Swedish study found diet, environment, health and genetics. They consist of far that lesbians react differently to AND too many compounds to be described as pheromones ( derivative 4,16-androstadien-3-one) themselves 4,5,11 . compared with heterosexual women. AND is ten times more abundant in human male sweat than female sweat8. PROOF ABOUT HUMAN PHEROMONES A study, published in Respirology in January 2016, Gustav Jäger a German doctor and hygienist is thought to showed that AND caused swelling in the erectile tissue of be the first scientist to put forward the idea of human female noses. This was taken as evidence that AND 1 pheromones. He called them anthropines and said that might be a functioning pheromone . Another contender they were lipophilic compounds associated with and for the role of human pheromone is . follicles that mark the individual signature of human There is some evidence that androstadienone, a odours. Lipophilic compounds are those that tend to component of male sweat, increases attraction, affects combine with, or are capable of dissolving in lipids 13-15 . mood and levels and activates brain areas linked In 1998, the path-breaking discovery carried out by Dr. to social cognition. One study found that and 31 Martha McLkintock in human pheromones field rostadienone increased cooperative behavior in males . described that those women stay in hostel together, stay , secreted only by males, has also been in a group in home like accommodation their physiology tested for its potential role as a pheromone. According to shows that there is synchronization of ; it some studies, androstenone increases a woman's mood, is probably because of the chemical scents released especially if she is presented with it close to the time of through sweat from those menstruating women body 16- ovulation. Overall, evidence for the existence of 20,25 . In recent advances in the field of human pheromones in humans is weak but it cannot be ruled out pheromones, scientists used scanning technique such as entirely. If human pheromones are ever found, the 30,32,33 PET (Positron Emission Tomography) scan to study the likelihood is that their effects are incredibly subtle . brain functions of selected 24 men and women while they Types of Pheromone: There are four principal kinds of 33,34 are exposed the odour emanating chemicals which are pheromones : almost identical to the human sex hormones such as 1. Releaser pheromones - They elicit an immediate and oestrogen. The expert scientist from the response, the response is rapid and reliable. They field of chemical signalling Dr. David Berliner analysed are usually linked to . these PET scan findings and concluded that women has a 2. Primer Pheromones - These take longer to get a ability to communicate with men and vice versa, these response. They can, for example, influence the findings also support that the human pheromones do development or reproduction physiology, exist. This opinion is based on the important observation including menstrual cycles in females, , that the human sex hormones like chemicals activate and the success or failure of pregnancy. They can specific areas of the brain which controls human alter levels. In some mammals, scientists behaviour 11,12,14 . Another scientist group form Karolinska found that females who had become pregnant and Institute under the leadership of Dr. Ivanka Savic, found were exposed to primer pheromones from another out that the hormone-like scents activates and turn on the male, could spontaneously abort the fetus. human brain’s specific area called as “hypothalamus”, 3. Signaler Pheromones - These provide which regular odours are not able to activates. They also information. They may help the mother to observed that the brains of women and men respond very recognize her newborn by scent (fathers cannot differently to the different sex hormones 27-29 . When men usually do this). Signaler pheromones give out our are allowed to smell the chemical similar to , genetic print. their brain’s hypothalamus became “turn on” but not 4. Modulator Pheromones - They can either alter or during smelling of testosterone-like chemicals, whereas synchronize bodily functions. Usually found in women’s hypothalamus has the exactly opposite sweat. In animal experiments, scientists found that response: their hypothalamus was turned on only by the when placed on the upper lip of females, they testosterone-like chemicals and not the estrogen-like one. became less tense and more relaxed. Modulator They have also observed the sexual disparity among the hormones may also affect a female's monthly specific sub-regions of the hypothalamus after the cycle. activation to specific smell stimuli 23,24,26 . Scientists

MedPulse International Journal of Physiology, Print ISSN: 2550-7613, Volume 3, Issue 2, August 2017 Page 16 Shrikant L Patil

Can Pheromones Make Us More Sexually offspring. I urge those of you who are not yet die-hard Attractive? - If these pheromones turn on areas of determinists not to view the effect of pheromones on mate the brain that control mood, hormones and sexual choice as a loss of agency, but as a gain of sensory behavior, one might then ask: "Can these chemicals ability, enabling us to make a more informed decision. make us more attractive?" The answer is: Maybe. Pheromones are just another way we can communicate. Researchers at the University of Chicago and University of Utah have found that the same sex REFERENCES hormone-like chemicals used in the Swedish study 1. Andrea Mazzatenta, can in fact have a pheromone effect by producing C. De Luca, A. Di Tano, M. Cacchio, C. Di Giulio, Miec changes in mood, heart rate, breathing, and body zyslaw Pokors 2016. Swelling of Erectile Nasal Tissue temperature. However, there is currently no Induced by Human Sexual Pheromone Chapter Respirology Volume 885 of the series Advances in indication these chemicals can actually increase 35,36 Experimental Medicine and Biology pp 25-30 or attraction . Many 2. Ben-Ari, E. T. 1998. Pheromones: What's in a name? companies have tried to capitalize on the potential BioScience, 48(7), 505-511. sex-specific effects of these chemicals by adding 3. Bensafi M, Brown WM, Tsutsui T, Mainland JD, them to their fragrances. But most of these companies Johnson BN, Bremner EA, Young N, Mauss I, Ray B, add hormones from animals such as and , so Gross J, Richards J, Stappen I, Levenson RW, Sobel N. 2003. Sex- derived compounds induce sex-specific they probably don't work. Pheromones are generally effects on autonomic function in humans. species-specific, so a perfume enhanced with Behavioral Neuroscience, 117(6), 1125-1134. 35-37 pheromones is really only useful for other pigs . 4. Berglund, H., Lindstrom, P., & Savic, I. 2006. Brain The promotions of one company that adds human response to putative pheromones in lesbian women. hormones to its fragrances claim the additives will Proceedings of the National Academy of Sciences, "put you and your partner at ease, boost your 103(21), 8269-8274. 5. Chen, D., & Jones, J. H. 2000. Human olfactory confidence, and contribute to a feeling of well being." communication of emotion. Perceptual Motor Skills, 91, The general idea is that pheromone perfume can 771-781. replace our naturally produced pheromones that have 6. Cornwell, R., Boothrowd, L., Burt, D., Feinberg, D., been washed off through bathing and hidden by Jones, B., Little, A., et al. 2004. Concordant preferences layers of clothing. If these claims are true, for opposite-sex signals? human pheromones and facial pheromones may make us more attractive to potential characteristics. The Royal Society, 27(1), 635-640. 7. Cutler WB, Friedmann E, McCoy NL. 1998. Pheromonal mates by bringing out our best qualities and allowing influences on sociosexual behavior in men. Archives of us to appear more self-assured and relaxed. That Sexual Behavior, 27(1), 1-13. "feeling of well being" may also make us a lot more 8. Cutler WB, Friedmann E, McCoy NL. 1998. Pheromonal pleasant to be around 37-39 . Pheromones as influences on sociosexual behavior in men. Archives of Therapeutics: The ability of these -like Sexual Behavior, 1(1), 13. chemicals to activate areas of the brain that control 9. Cutler WB, G. E. 2002. Pheromones, sexual attractiveness and quality of life in menopausal women. hormones indicates they may have more broad- Climacteric, 5(2), 112-121. ranging therapeutic value as well. For example, 10. Cutler WB, G. E. 1998. Wellness in women after 40 Pherin Pharmaceuticals is currently developing years of age: The role of sex hormones and pheromones. numerous synthetic pheromones that it hopes will be Disease-a-Month, 44(9), 421-546. effective in decreasing symptoms of anxiety 11. Dalton, P., Doolittle, N., & Breslin, P. A. S. 2002. disorders, premenstrual syndrome in women, and Gender-specific induction of enhanced sensitivity to . Neuroscience, 5(3), 199. prostate enlargement in men. 12. Diamond, J., Dalton, P., Doolittle, N., & Breslin, P. 2005. Gender-specific olfactory sensitization: Hormonal and CONCLUSION cognitive influences. Chemical , 30(1), 224-225. The previously discussed studies have suggested that 13. Forker, C. 1985. The green underworld of early pheromones can communicate information about genetic shakespearean tragedy. Shakespeare Studies, 25. 14. Grosser BI, Monti-Bloch, L., Jennings-White, C., & compatibility, sexual orientation and gender by affecting Berliner, D. 2000. Behavioral and electrophysiological humans unconsciously and physically. Reproduction is effects of androstadienone, a human pheromone. the most important aspect when it comes to being a Psychoneuroendocrinology, 25(3), 289-99. successful species, comparable only, perhaps, to survival. 15. Hays, W. S. T. 2003. Human pheromones: Have they Of course it makes , then, that there are mechanisms been demonstrated? Behavioral Ecology and beyond our control that urge us not only to procreate, but Sociobiology, 54(2), 89-97. 16. Jacob, S., Garcia, S., Hayreh, D., & McClintock, M. with mates that will result in the most successful 2002. Psychological effects of musky compounds:

Copyright © 2017, Medpulse Publishing Corporation, MedPulse International Journal of Physiology, Volume 3, Issue 2 August 2017 MedPulse International Journal of Physiology, Print ISSN: 2550-7613, Volume 3, Issue 2, August 2017 pp 15-18

Comparison of androstadienone with and 28. Savic, I., Heden-Blomqvist, E., & Berglund, H. 2009. muscone. Hormonal Behavior, 42(3), 274-284. Pheromone in humans: What can be 17. Jacob, S., Hayreh, D., & McClintock, M. 2001. Context- learned from olfactory loss. Human Brain Mapping, dependent effects of steroid chemosignals on human 30(9), 3057-3065. physiology and mood. Physiological Behavior, 74(1), 15- 29. Savic, I., Berglund, H., & Lindstrom, P. 2005. Brain 27. response to putative pheromones in homosexual men. 18. Jacob, S., Kinnunen, L., Metz, J., Cooper, M., & Proceedings of the National Academy of Sciences, McClintock, M. 2001. Sustained human chemosignal 102(20), 7356-7361. unconsciously alters brain function. Neuroreport, 12(11), 30. Singh, D., & Bronstad, P. M. 2001. Female body odour is 2391-4. a potential cue to ovulation Proceedings: Biological 19. Jacob, S., McClintock, M., Zelano, B., & Ober, C. 2002. Sciences, 268(1469), 797-801. Paternally inherited HLA alleles are associated with 31. Speilman, A., Zeng XN., Leyden, J., & Preti, G. 1995. women's choice of male odor. Nature Genetics, 30, 175. Proteinaceous precursors of human axillary odor: 20. Jacob, S., & McClintock, M. 2000. Psychological state Isolation of two novel odor-binding proteins. Experientia, and mood effects of steroidal chemosignals in women in 51(1), 40-47. men. Hormonal Behavior, 37(1), 57-78. 32. Stern, K., & McClintock, M. 1998. Regulation of 21. Jacob, S., Spencer, N., Bullivant, S., Sellergren, S., ovulation by human pheromones. Nature, 392 Mennella, J., & McClintock, M. 2004. Effects of 33. Takami, S. 2002. Recent progress in the neurobiology of breastfeeding chemosignals on the human menstrual the . Microscopy Research cycle Human Reproduction, 19(2), 422-429. Technology, 57(3), 228-250. 22. Kohl, J., Atzmueller, M., Fink, B., & Grammer, K. 2001. 34. Tiridelli, R., Dibattista, M., Pifferi, S., & Menini, A. Human pheromones: Integrating neuroendocrinology and 2009. From pheromones to behavior. Physiol Rev, 89, . Neurological Endocrinology Letters, 22(5), 921-956. 309-321. 35. Touhara, K., & Vosshall, L. B. 2009. Sensing odorants 23. Marazziti D, Masala I, Baroni S, Polini M, Massimetti G, and pheromones with chemosensory receptors. Annual Giannaccini G, et al. 2010. Male axillary extracts modify Review of Physiology, (71), 307-332. the affinity of the platelet serotonin transporter and 36. Wedekind, C., & Penn, D. 2000. MHC genes, body impulsiveness in women. Physiological Behavior. odours, and odour preferences Nephrology Dialysis 24. Martins, Y., Preti, G., Crabtree, C., Runyan, T., Vainius, Transplantation, 15, 1269-1271. A., & Wysocki, C. 2005. Preference for human body 37. Wyart, C., Webster, W. W., Chen, J. H., Wilson, S. R., odors is influenced by gender and sexual orientation. McClary, A., Khan, R. M., et al. 2007. Smelling a single Psychological Science, 16(9), 694. component of male sweat alters levels of cortisol in 25. McClintock, M. 1998. Whither ? women. Journal of Neuroscience, 27(6), 1261-1265. Annual Review of Sex Research, 9, 77. 38. Wysocki, W., & Preti, G. 2004. Facts, fallacies, , 26. Preti, G., Wysocki, J., Barnhart, K., Sondheiner, S., & and frustrations with human pheromones. The Leyden, J. 2003. Male axillary extracts contain Anatomical Record Part A, 1201-1211. pheromones that affect pulsatile secretion of luteinizing 39. Zhou, W., & Chen, D. 2008. Encoding human sexual hormone and mood in women recipients. Biology of chemosensory cues in the orbitofrontal and fusiform Reproduction, 68(6), 2107-2113. cortices. Journal of Neuroscience, 28(53), 14416-14421. 27. Savic, I. 2004. Imaging of olfaction and gustation. Nutritional Review, 62(11), 205. Source of Support: None Declared Conflict of Interest: None Declared

MedPulse International Journal of Physiology, Print ISSN: 2550-7613, Volume 3, Issue 2, August 2017 Page 18