Pheromones are substances that can be smelled and not seen. There have even been studies to suggest pheromones can be just as effective if they are not smelled. Pheromones have always carried messages to individuals of the same species in the animal kingdom, and humans are no different. But as we have come to rely on our other senses, our reliance on pheromone signals has been greatly diminished, but our subconscious can still pick up on it, we just don't always realize it.

Pheromones are carried in the air and are created by everyone's body. When wearing clothes, your temperature rises, creating a ?smell? that will evaporate from your body via the highest opening in your clothing, typically at the neck of your shirts. This pheromone signal is then carried to others, who will ultimately look at your face, as this is where your signal left you from. For this reason, many people notice another's face right off the bat before their other senses take over and take in other attributes of the other person.

The pheromone signals that we can give off can be categorized into a couple categories: fear, aggression and sexual receptiveness. When a person is scared, the chemical change in their pheromone signal can be so strong as to be read by animals, thus the saying that wild animals can smell your fear. Pheromone signals that trigger aggression in others can cause someone to feel aggressive toward another person for an unknown reason; this pheromone signal is generally passed between males who are attracted to the same female. Sexual receptiveness pheromone signals are those that females give off to entice and let males know that they are available sexually.

Pheromones that are created generally peak around 18 to 20 years of age and begin to wane at approximately 40 years of age. The signals that 18 year olds give off are so strong that people of all age groups are generally drawn to look at them. However, there have been studies that show direct correlation to pheromones and the physiological reactions that they cause to our sense of smell. The better a person's sense of smell, the stronger his or her reaction will be to a pheromone signal that they receive. Because of this correlation and the fact that people around the age of 40 have a lower pheromone signal or pheromone reaction could be tied to the fact that age affects one's sense of smell. And as the sense of smell decreases and becomes less prominent, so too does the reaction to pheromone signals that may be sensed.

Pheromone signals are constantly being traded back and forth among individuals, whether it is between two women, two men or a man and a woman. We are not as receptive to them as other animals seem to be because we have come to rely on other senses and factors to maintain our livelihood. But, if you find yourself attracted to someone who is not your ?type?, you can bet that subconsciously your nose has caught onto his or her scent and become quite fascinated.