The mixture of chemicals in Scent of Eros for men has been shown to increase observed flirtatious behaviors and increase self-reported levels of attraction in a study of college women. The observed interaction was during 15 minutes of exposure to the mixture (or not), being worn by a male study participant. Many people are aware that original research on the effects of human pheromones on menstrual synchrony came in reports from a study of college women. I hope that additional studies of human pheromones will, like the 2007-2009 series of studies by Kelahan, Hoffmann and Kohl, continue to detail the chemicals used, the methodology used, and report on the time that might be expected for human pheromones to cause a change in behavior (e.g., 15 minutes).
Given the reported findings by Kelahan, Hoffmann and Kohl, I am now willing to write about product comparisons. I continue to see reports that examine the effects of interactive neuronal systems associated with reproductive sexual behavior, but the affect on sex differences in behavior is misrepresented. Is oxytocin a pheromone? I don’t know how oxytocin could directly affect behavior without first effecting GnRH pulsatility in mammals. This suggests to me that the direct effect of pheromones on GnRH is far more important to behavioral development in all species, and that focus on other downstream effects of hormones like oxytocin directs attention away from biological cause and effect.
To the consumer, this means that advertisements for products that claim to contain the pheromone oxytocin are probably deliberately misleading. Nothing that I’ve read indicates that oxytocin is a pheromone. Simply put, marketers seem to be trying to sell products containing a hormone, by telling consumers that the hormone is a pheromone. This is somewhat equivalent to telling consumers that hormones like testosterone or estrogen can be included in fragrance products that will then make these hormones act like pheromones that influence behavior.
Some people may know and recall that a similar approach was used by Winnifred Cutler of the Athena Institute when she first began marketing a product that she said (on national television) contained DHEA (dehydroepiandrosterone). There has never been any evidence that suggested to me that this hormone could act like a pheromone to influence behavior. And studies that have been used by Cutler to help market her products are deliberately vague about what pheromone (if any) is used to achieve a behavioral affect in 74% after study participants used the product for eight weeks.
Product comparison of exposure to affect time: Scent of Eros: 15 minutes; Athena product: 8 weeks; Oxytocin product: no data
What prompted this post?
Jae Young Seong was very kind to send the uncorrected proof of an excellent (in press) review article. Revisiting the evolution of gonadotropin-releasing hormones and their receptors in vertebrates: Secrets hidden in genomes General and Comparative Endocrinology by Dong-Kyu Kim, Eun Bee Cho, Mi Jin Moon, Sumi Park, Jong-Ik Hwang, Olivier Kah, Stacia A. Sower, Hubert Vaudry, Jae Young Seong
The article excludes invertebrates but addresses the influence of GnRH and the accuracy of my model, which has its origins in yeast. Kim et al (in press) write that “Neuropeptides and their receptors originating from a common ancestral gene have become diversified through evolutionary processes, such as gene/chromosome duplication and gene modification, generating families of related yet distinct peptides and receptors.” Therein lies the reason for my comments on their review. In my review, I wrote:
“The overall influence of mammalian olfactory/pheromonal input on hypothalamic GnRH release and on LH release from the pituitary represent a highly conserved effector system that includes genes that code for the peptide ligand (i.e., GnRH) and the cell-surface receptor: the GnRH receptor (GnRHR). The result of this genetic conservation of GnRH and its receptor is the physiological regulation of sexual reproduction across species. The transition from asexual to sexual reproduction involves two organisms that incorporate the equally well-conserved GnRH-directed, GnRHR-enabled neuroendocrine system signaling mechanism and the MHC/HLA-directed immune system signaling mechanism. These signaling mechanisms are involved in the chemical discrimination of self from non-self, genetic diversification, and the neuroendocrine response to non-self chemical signals, like olfactory/pheromonal input from the social environment.”
Now that the review by Kim et. al., has more fully detailed the evolution of GnRH in vertebrates, it will be interesting to learn more about whether something other than GnRH and its receptor diversification plays as important a role in the evolution of the olfactory and immune systems, and in the scientifically shown effectiveness of human pheromone-enhanced products.