It is hypothesized that humans are able to produce pheromones and pick up on those pheromones produced by other members of the human race. This hypothesis is not entirely unreasonable considering how important pheromone use is to other mammals such as rats, mice and dogs who use these to mark territories and signal to the opposite sex that they are ready to mate.
Pheromones essentially function as external hormones in the fact that they are small chemicals secreted from the body that have the power to influence the physiology or behavior of a conspecific (member of the same species).
Martha McClintock first published evidence for the existence of human pheromones in 1971 in the peer-reviewed journal Nature. This study was conducted on women living together in a college dorm setting. It was discovered that the menstruation cycles of women who spent great amounts of time together (such as two best friends) would synchronize over time. This provided very strong evidence that people are able to produce pheromones which affect the physiology of other members of the human race in various ways.
According to a 2001 review article of this pheromone issue, sufficient evidence from various research studies has been accumulated to confidently state that humans do, indeed, produce a certain level of pheromones.
The above findings largely satisfy the classic definition of pheromones: “Substances which are secreted to the outside by an individual” (in humans: sweat) “are received by a second individual of the same species, in which they release a specific reaction” (in humans: change in timing of ovulation and sex-specific changes in physiological measures, levels of hormones, and brain activity) “for example, a definite behavior or a developmental process.” It is only this last component of the classic definition that has not been decidedly demonstrated in humans.One of the strongest arguments against the human pheromone hypothesis argument is the fact that it is uncertain whether or not humans have a functional vomernasal organ (VNO). This organ is part of the accessory olfactory system and is the main, though not the only, manner in which the previously mentioned mammals sense the pheromones from other conspecifics. It was stated in this same 2001 review article that even though the functionality of the human VNO is not certain, this does not necessarily mean that humans cannot sense pheromones. Pheromones can be taken up and processed by way of the main olfactory system possessed by humans.
Obviously, whether or not people produce pheromones will not be of much interest to the general public if the only power they have over the human body is synchronize menstruation timing of unsuspecting females.
However, if it was discovered, for example, that higher concentrations of these pheromones could increase one’s chance of ‘getting lucky’, the general public’s interest in these little compounds would significantly increase. Most scientific work today dealing with human pheromones is focused on the two hormone-like chemicals ‘androstadienone’ (which is thought to function as a sex attractant to women) and ‘estratetraenol’(which is thought to function as a sex attractant to men). Both of these compounds are found in human sweat.
Further work from McClintock and Jacob in 2000 has shown that the effects of these hormones, while they do have very interesting effects on brain function and psychological state, are not as powerful as the advertising companies are claiming. Nevertheless, other works, such as that of Norma McCoy, PhD, in 2002 and Winnifred Cutler, PhD, in 1998 have found that the male pheromone additive to a perfume significantly increased the man’s likelihood of having sex.
However… The results obtained by Winnifred Cutler, PhD, in 1998 may or may not be partially biased as she was one of the founders of a certain company specializing in perfumes containing pheromone additives. Even though the scientific work being done with these two compounds have not shown the simple cause-and-effect relationship between these products and sex, many many companies are still making profits on items such as candles, lotions and perfumes that are infused with high concentrations of these potentially sexy human pheromones.
My very favorite site advertising pheromone perfumes was this link which shows an attractive, presumably half-naked model seductively explaining the nuances of how this chemistry is supposed to work....