Do humans secrete chemicals that attract the opposite sex? Some cheesy advertisements in magazines would make one believe pheromones exist. When's the last time you said "that girl/guy is butt ugly", then walked closer to smell her/him and said "damn girl/boy, you fine!"?
There are many perfume companies offering products that claim to contain human pheromones, and this one has an interesting claim on its home page that attempts to convince potential customers:
- "Human Sex Pheromones are natural chemical scents the body produces in order to attract others. Animal Sex Pheromones are well documented in the animal kingdom as the force that controls all social behaviour, including mating. Scientists are now finding that human behavior is also heavily influenced by Human Pheromones, the ultimate invisible social magnets. By intensifying the sex pheromones that already occur naturally, you will experience not only a boost in confidence, but also increased sex appeal. ..." (Source: http://www.love-scent.com/)
Unfortunately, there don't seem to be any references to studies on that web site regarding any types of Pheromones -- I would like to see even one study they're relying on to back up their claim that "Animal Sex Pheromones are well documented in the animal kingdom as the force that controls all social behaviour, including mating," which is a good reason for you to be skeptical.
People do have olfactory systems that help to discern smells though, and since people do exhibit a variety of natural odours (possibly influenced by a combination of genetics, state of health, diet, exercise habits, etc.), I would expect the effects to be at least somewhat selective since what is perceived as a bad smell by one person may be a good smell to another. There is an interesting paper on this that references a long list of studies, including some studies performed on rats (in particular, see the sections entitled "Human Pheromones" and "Is a Mammalian Model Applicable to Human Behavior?"):
Human Pheromones: Mammalian Olfactory, Genetic, Neuronal, Hormonal,
and Behavioral Reciprocity and, Human Sexuality (May 16, 1996)
The first paragraph in the "Introduction" section (paragraph 3) reads:
- "Pheromones are social-environmental chemical stimuli (e.g., odors). They are produced by one individual and detected by another individual of the same species. Typically, pheromonal communication elicits physiological and behavioral changes. These changes are expected to benefit both individuals. Pheromones exert their influence whether or not an animal is conscious of pheromone detection; the animal may not be aware that it is responding to an odor."
The first paragraph in the "Human Pheromones" section (paragraph 9) reads:
- "Evidence from human studies that suggests we produce pheromones and that we are not exempt from prenatallypredisposed mammalian olfactorygeneticneuronalhormonal relationships involving pheromones, genes in GnRH neurosecretory neurons, and the influence of GnRH secretion on levels of other hormones, is found in the following ..."
The fifth paragraph in the "Is a Mammalian Model Applicable to Human Behavior?" section (paragraph 53) reads:
- "It is difficult to validate cross-species comparisons because of inherent difficulties either in carrying out controlled human studies of olfactory transduction or of its association with odor hedonics, mood, memory, motivation, expressions of effect, cognitive behavioral state, potentiating responses to other stimuli (see Ehrlichman & Bastone, 1992 for review), and neural circuitry. This failure to validate cross-species comparisons contributes to a common belief among scientists and laypersons: that--unlike many other mammals--humans learn more through visual cues than through socialenvironmental chemical cues. However, just as a child born blind does not learn to prefer one color to another, a child who is born anosmic does not develop odor preferences. Similarly, innate differences in visual or other sensory acuity suggest that many mammalian, including human, behaviors are initially genetically predisposed. Subsequently, behaviors appear to be conditioned through olfactory and other sensory stimuli (Kirk-Smith, 1996). For instance, it seems likely that our food preferences are based upon innate differences in the chemical senses (taste and olfaction), which are present before we are able to respond to a food's visual appeal and that, subsequently, food preferences may be based upon the pairing of olfactory (or taste) stimuli with a visually conditioned response to the sight of an appetizing item."
Hypothetically, if these pheromones were powerful enough to have an immediate effect on a person so as to completely change their perception of how attractive another person is, then I strongly suspect that these products would likely be classified as dangerous (since they could be used to commit crimes of a sexual nature, etc.) by local government regulators (just like many pharmaceuticals are) with their distribution prohibited (which would consequently make it illegal to sell).
So, in an attempt to answer your questions: It seems that Humans do secrete these chemicals, but I would classify the rest of the exaggerations and claims by the marketers as something along the lines of mythical.
To answer your question "Do human pheromones exist" the answer is most certainly "yes". That's what body odour is.
Your question should be "Do human pheromones work the way the scam artists say they do". The answer is almost categorically "no". It's already pretty apparent that your natural pheromones aren't attracting the opposite sex like sharks to blood. More than likely the reason for this is because human beings just don't operate (or mate) like dogs or moths. We all meet and mate through social mechanisms instead. I suspect that the effectiveness of your pheromones on other people is a highly subjective and individual thing and just as importantly, only part of the equation.