Regulation of ovulation by human pheromones

Abstract

Pheromones are airborne chemical signals that are released by an individual into the environment and which affect the physiology or behaviour of other members of the same species. The idea that humans produce pheromones has excited the imagination of scientists and the public, leading to widespread claims for their existence, which, however, has remained unproven. Here we investigate whether humans produce compounds that regulate a specific neuroendocrine mechanism in other people without being consciously detected as odours (thereby fulfilling the classic definition of a pheromone). We found that odourless compounds from the armpits of women in the late follicular phase of their menstrual cycles accelerated the preovulatory surge of luteinizing hormone of recipient women and shortened their menstrual cycles. Axillary (underarm) compounds from the same donors which were collected later in the menstrual cycle (at ovulation) had the opposite effect: they delayed the luteinizing-hormone surge of the recipients and lengthened their menstrual cycles. By showing in a fully controlled experiment that the timing of ovulation can be manipulated, this study provides definitive evidence of human pheromones.

The main and the accessory olfactory systems interact in the control of mate recognition and sexual behavior

“…With regard to mother-young relationships, the rabbit mammary pheromone 2-methylbut-2-enal present in the milk of the mother induces nipple-searching behavior in pups [94]; removal of the VNO has no effect on the nipple-search behavior while ablation of the MOE abolishes it completely [39]. Finally, with regard to humans, who do not have a functional VNO and in whom an AOB has never been identified, it has been shown that exposing women with normal menstrual cycles to axillary extracts from women in their follicular phase shortens the length of the recipient's menstrual cycle [104]. Furthermore, Shinohara et al [100] reported that women exposed to female axillary secretions showed changes in LH pulses.…”

Facts, fallacies, fears, and frustrations with human pheromones

“…Where this occurs, the effects are thought to result from exposure to pheromones from a driver female (Russell et al, 1980) whose cycle is thought to remain unaffected but who provides the temporal cues to synchronize the cycles of other females [ ); see Wilson (1992) for a critique]. Depending on the stage of the cycle of driver female, these cues appear either to accelerate or to retard the onset of ovulation in recipient females [ (Stern and McClintock, 1998); for an alternative interpretation, see comments by Whitten (1999)]. …”

The search for human pheromones: the lost decades and the necessity of returning to first principles

“…Pheromone-mediated menstrual synchrony (the convergence in the cycles of women living in close proximity) was reported in 1998 by Stern & McClintock [67]: extracts of armpit secretions from women at different stages in their cycles were put on the upper lip of other women. There has been lively debate about the phenomenon of synchrony itself, quite apart from pheromones.…”