What Are Pheromones?
Pheromones are chemical molecules released in humans, animals, and insects. These molecules are secreted to the outside and received by other members of the same species (typically by members of the opposite sex, and members of the same sex or both sexes). Pheromones are capable of eliciting behavioral and hormonal responses from those who receive them.
Where Are Pheromones Found in the Body?
The signaling molecules are generally present in most animals' bodily fluids and secretions. This includes sweat, urine, breast milk, saliva, semen and vaginal fluids, and even breath. Given that they are secreted outside the body and influence other individuals, pheromones are ectohormones (unlike most other hormones secreted within the body that influence the person's bodily functions).
What Is the Function of Pheromones?
Pheromones across different species perform certain functions that act as triggers or cues to responses from other members of the same species:
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Sexual arousal trigger.
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Raising the alarm.
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Warning system.
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Territory marking.
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Bonding hormone.
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Food trail marker.
What Are the Different Types of Pheromones?
There are four main classes of pheromones:
- Releaser Pheromones - Releaser pheromones cause an immediate, reliable and specific response related to sexual attraction. This may either be sexual attraction or repulsion and is a short-term response.
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Primer Pheromones - Primer pheromones cause behavioral changes relating to behavior, development, and reproductive development. The responses mediated by primer pheromones take longer and are also long-lasting.
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Signaler Pheromones - Provide information about an individual. Signaler pheromones can give out genetic odor prints, which provide specific information based on the sense of smell alone.
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Modulator Pheromones - These pheromones affect emotions, cause mood changes, and are capable of synchronizing bodily functions. They may also affect the female menstrual cycle.
Apart from the four main classes, pheromones also fall into several other smaller but distinct categories. These pheromones are not all released by humans but are present in different species:
- Aggregation Pheromones - Pheromones are produced by both sexes and attract individuals of both sexes.
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Alarm Pheromones - Pheromones can trigger a flight response when confronted with a predatory attack.
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Epideictic Pheromones - Pheromones are released as a warning or display to other members of the same species that a particular region has been claimed by the hormone releaser so that they will go elsewhere.
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Territorial Pheromones - These pheromones are released to mark territories through boundaries. They are released into the environment, usually by animals.
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Trail Pheromones - Trail pheromones are released to mark a path - for example, they may lead the way to a food source.
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Sex Pheromones - Sex pheromones cover a range of sexual activity, from indicating readiness for breeding to providing information about species and genotype and attracting potential mates.
How Do Pheromones Work in Humans?
The role of pheromones in humans is as yet not fully understood. This is because the vomeronasal organ or Jacobson’s organ in humans appear to have little to no functionality. While the organ is quite apparent in a developing fetus, it undergoes atrophy before birth. The vomeronasal organ is linked to pheromone detection; its absence in humans raises questions about whether humans can actually sense pheromones. Studies on humans have concluded that even if humans respond to pheromones, they most likely do so with their olfactory systems (sense of smell).
This conclusion has been propounded especially in light of the fact that certain pheromones have been identified as probably capable of eliciting some semblance of a response from humans. These include:
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AND - AND or 4,16-androstadien-3-one is a progesterone derivative that has been demonstrated to cause some swelling in the erectile tissue of female noses. While not conclusive proof that AND is a pheromone, it has not been ruled out.
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Androstenone - This is a substance secreted by males that apparently improves a woman’s mood and cognition while also increasing her libido when she is close to ovulation. However, since women naturally experience a surge in libido around the time of ovulation anyway, there is probably no sufficient evidence to prove that androstenone can cause this reaction on its own.
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Androstadienone - Another purely male secretion, androstadienone is present in male sweat. It is supposedly capable of increasing attraction, improving social cognition, and influencing moods. In addition, it can improve cooperation between males almost like a male bonding or camaraderie influence.
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Androstenol - This hormone has influenced subjective mood, particularly in women during ovulation.
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Estratetraenol (EST) - This hormone is found in women's urine and has been proposed as a pheromone, based on its ability to influence the male perception of a person's face or walking style as feminine.
Additional functions that are supposedly mediated through pheromones include:
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Female Menstrual Cycles - Another possible indication of pheromone functioning in humans is the synchronization of female menstrual cycles. Evidence for this phenomenon has been demonstrated through the McClintock effect. This effect essentially refers to menstrual cycle synchronization through odor cues. Researchers demonstrated that when women are exposed to the scent of sweat from other women, their menstrual cycles can change. The change may be the acceleration or slowing down of menstrual cycles, depending on the time around ovulation that the scent is received.
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Vaginal Secretions - There have been suggestions that vaginal secretions may contain a type of sex pheromone called copulin which can cause changes in a male’s perception of and attraction to a female. Vaginal secretions contain acetic acids that can fluctuate along with hormone levels during the menstrual cycle. While researchers have demonstrated differences in vaginal secretion odors before and after sexual activity, the role of vaginal secretions as pheromones is less well-established.
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Male Axillary Secretions - Male axillary secretions or underarm secretions, when placed under women’s noses, have demonstrated the ability to increase relaxation and reduce stress in these women. This indicates a modulatory pheromone type of effect in male axillary secretions. In addition, when placed on a female’s upper lip, these secretions are reportedly capable of regulating menstruation.
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Babies and Mothers - Sleeping babies have demonstrated the ability to distinguish between pads worn by their mothers versus other women through scent. While the exact mechanism is unclear, it does suggest possible pheromone activity.
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Sexuality - Humans with varying sexual identities and interests demonstrate an inclination for body odors and secretions from genders that match their interests and sexuality. A pheromone-based link may therefore exist between sexual orientation and brain activity that influences personal choices.
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Facial Characteristics - Men and women have shown a preference for feminine and masculine face shapes, respectively, in correlation with pheromones. Sex pheromones and sexually dimorphic facial characteristics may thus be correlated.
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Psychosocial Factors - Pheromones can cause changes from a psychological standpoint. They can trigger parental sexual attraction responses (Oedipal complex), fertility changes, and mood changes.
Conclusion
The presence and possible uses of pheromones in humans, while not fully known, are important in understanding sexual attraction and hormonal triggers. Understanding pheromone activity is also essential in promoting sexual health, reproductive health, and psychosexual attraction. Further studies could establish better roles for pheromones in several human interaction situations
