Pheromones are chemical signals that are released by animals and humans that can impact the behavior and physiology of others. Male pheromones in particular can convey information about health, dominance, and genetic compatibility to potential mates.
What are pheromones?
Pheromones are substances that are secreted externally by an individual and received by a second individual of the same species, impacting their behavior or physiology. In animals and insects, pheromones play an important role in conveying information about food sources, dangers, and reproductive status. In humans, pheromones are detected through the vomeronasal organ (VNO), a sensory organ located in the nasal cavity.
Types of pheromones
There are several different types of pheromones:
- Sex pheromones: Convey information about reproductive status and can trigger attraction/sexual behavior.
- Aggregation pheromones: Lead others to assemble in a specific location, like bees gathering at a hive.
- Alarm pheromones: Warn others of danger, like ants releasing pheromones when attacked.
- Territorial pheromones: Mark boundaries of territories and discourage trespassers.
In humans, the focus has been primarily on sex pheromones and their role in attraction between individuals.
How pheromones work
Pheromones are generally airborne chemical substances that travel to the VNO or main olfactory system. There, the molecules bind to specialized receptor cells that detect and process the pheromone signal. This triggers a cascade of neurological and physiological responses, altering hormone levels, brain activation patterns, emotion, and behavior.
Research suggests the limbic system of the brain plays an important role in processing these responses. The specific effects depend on the type of pheromone detected.
In many animal species, males release pheromones that can directly influence female reproduction. The male pheromones coordinate the reproductive cycles of females to optimize chances of successful mating.
Evidence now suggests that human male pheromones may also convey information to females, albeit in more subtle ways. Studies have found they may provide signals about:
- Genetic quality
- Reproductive immunity
- Dominance and masculinity
- Sexual orientation
Male pheromones appear capable of influencing female perception, attractiveness ratings, hormone levels, and even menstrual cycles when exposure occurs. The effects are believed to be mediated through the limbic system emotional centers of the brain.
One key molecule identified as a potential human male sex pheromone is androstadienone. Androstadienone is produced in the testes, adrenal glands, and sweat glands. It is a metabolite of testosterone and found at high levels in male semen and sweat.
Research shows that females demonstrate the following effects in the presence of androstadienone:
- Increased levels of cortisol
- Elevated mood
- Enhanced physiological arousal
- Improved cognitive performance
However, the effects of androstadienone exposure appear quite variable depending on the menstrual cycle. Changes in mood, sexual arousal, neurological patterns, hormone levels, and social perceptions have been reported and seem dependent on cycling hormones in females.
Androstenol is another candidate for human male pheromone function. Androstenol is found in male sweat and skin and has a mild musky odor. Studies show that women exposed to androstenol rate photographs of men as more attractive. It also increases comfort and conversation closeness in social settings according to some research.
Androstenone is produced by testes and adrenal glands in males. While detectable in fresh male sweat, its concentration increases significantly in older sweat as degradation releases more androstenone from conjugates. The smell has been described as musky, urinous, sweaty and even boar-like in higher concentrations. While it may act as a pheromone, females also demonstrate highly variable sensitivity to this odor.
How do male pheromones smell?
Despite evidence that pheromones like androstadienone and androstenol do convey sexual and social signals, they have little odor themselves. The “smell” of pheromones is often confused with the perceptible odors that act as carriers, such as sweat, urine, and skin secretions.
Pure synthesized human pheromones are essentially odorless. They impart no scent of their own. However, the natural bodily fluids that contain pheromones often have distinctive smells from metabolic byproducts. The actual odor is incidental to pheromone content and social messaging.
For example, androstenone is described as musky, urinous, or boar-like at high concentrations. But this reflects odorants within the sweat or urine itself. Pure androstenone is nearly odorless with a threshold below what most can detect by smell.
While they may trigger behavioral or physiological effects at a subconscious level, human male pheromones themselves are essentially scentless. Their impact arises from the hidden signals they convey rather than any obvious smell.
Although odorless, pheromones rely on bodily fluids and secretions to transport them to others. These fluids often have distinctive smells that become associated with pheromone signals.
- Sweat – Can take on a musky, rich scent as it ages and pheromone content changes.
- Urine – Develops a strong ammonia odor related to breakdown of urea.
- Saliva – Has no strong smell itself but contains odorous digestive enzymes when fresh.
- Semen – Smells bleach-like due to alkaline pH and gonadotropins like luteinizing hormone.
So while male pheromones themselves are odorless, they may elicit scent-related associations or be confused with the odors of their carriers. The distinctive smells are incidental rather than integral to pheromone signaling.
Do pheromone perfumes and colognes work?
There are now a wide variety of pheromone-based fragrances, body sprays, and oils that claim to act as aphrodisiacs and attractants. However, the efficacy of these commercial products is debated.
- Many contain synthetic human pheromones like androstadienone, androstenone, and androstenol as active ingredients.
- However, these molecules are present in much lower concentrations than naturally found in sweat and other bodily excretions.
- Other fragrances and masking scents are added in abundance which can overwhelm the pheromone component.
- While animal pheromones have clear, potent effects, human pheromone impacts are more subtle and variable.
In summary, commercial pheromone colognes and perfumes are unlikely to have significant pharmacological effects on human attraction or sexual behavior. Any impacts are probably small and contingent on individual body chemistry.
Male pheromones such as androstadienone, androstenone, and androstenol can influence female perceptions, hormones, mood, and behavior in some settings. However, the molecules themselves are essentially odorless. Any associated scents arise from carrier secretions rather than integral to the pheromone signaling itself.
While pheromone-based colognes claim to boost attraction, research is lacking to support significant effects. But male pheromones do appear capable of subtle impacts mediated through brain emotional centers. Future research may unlock more ways that male pheromones naturally signal mate characteristics and compatibility through concealed chemical channels.