The largest organ in the human body, the skin contains three distinct glands that are thought to generate pheromones: the apocrine, sebaceous, and eccrine glands.
The main function of the eccrine glands is to produce an odorless watery perspiration and move it to the surface of the skin. When this odorless liquid evaporates from the skin, we are kept cool and protected from overheating. The apocrines produce a strong scent and vary greatly in size and occurrence among individuals. They are dotted around the body but are concentrated in the armpits, the groin, and the nipple area. The apocrines produce the instantly recognizable smell of body odor, which gets its strong scent from the mingling of apocrine gland secretions with bacteria living on the skin. The apocrines kick into high gear during puberty, which explains why adolescents experience a sudden onset of powerful body odor.
The sebaceous glands are located throughout the body as well, but are concentrated on the face, forehead, ears, and scalp. These glands produce an oily substance that provides an ideal breeding ground for the bacteria living on human skin.
After these glands (with the apocrines leading the way) produce pheromones, the molecules then make their way to the , surface of the skin. In just one hour, humans can shed as many as one thousand skin cells per square centimeter of skin; this rapid sloughing of skin protects the body against bacteria. When j the skin sheds, bacteria have a harder time penetrating through the protective barrier and entering the body.
Skin ﬂakes, each composed of many thousands of skin cells, are packed with pheromone molecules. When a skin ﬂake detaches from the skin and starts traveling through the air, the : pheromone molecules can then be released to do their work. This is a very basic explanation of a complicated physiological process, but it serves to illustrate in a simple manner how , pheromones move from your body to the pheromone-receiving; systems of the people with whom you come into contact. Before pheromones reach the skin, however, they must be exposed.
One theory of pheromone production involves dehydroepiandrosterone (DHEA), which sex therapist and researcher Dr. Theresa Crenshaw calls “the mother of all hormones.”
DHEA and Pheromones: A Possible Link
DHEA is a sex hormone with an impressive repertoire. As a possible precursor to human pheromones, it is a vital component of everyone’s body chemistry.
In addition to its role in pheromone production, DHEA performs a number of important functions within the human body. For example, DHEA is thought to boost the immune system, improve brain function, act as an antidepressant, reduce levels of cholesterol in the blood, and encourage bone growth. This wonder-hormone also has the ability to boost a person’s sex drive, or libido. During orgasm, DHEA levels in the brain soar.
Classified as a steroid hormone, DHEA metabolizes into pheromones mainly through action in the adrenal glands, which are located on the kidneys. DHEA is also produced in the testicles, the ovaries, and the brain.
In The Alchemy of Love and Lust, Dr. Theresa Crenshaw says DHEA is “a most versatile hormone that first and foremost has the potential to manipulate our sexual selections through smell.” However, now that the sixth sense has been discovered, we can say that our sexual selections are driven not only by smell, but also by pheromone reception. DHEA levels peak when a person ls in his or her mid twenties—the time in the life cycle when mate selection and sexual activity are heightened as the two sexes prepare to have children. Levels begin to drop when adults reach their mid thirties.
While we might not be consciously aware of the effects of DHEA, each of us was exposed to the hormone in the womb. A growing fetus is enveloped in DHEA. In fact, the fetus produces DHEA in concentrations that eclipse other hormones, including the prominent sex hormones estrogen and testosterone.
The VNO: The Pheromone Sensor
One of the most exciting topics now under investigation is how humans process pheromonal messages. Scientists have been eager to determine whether humans possess the anatomical conduit for transmitting these messages to the brain. Since pheromones exist, the human body must contain a pathway that moves these chemical messages to the brain. A component of that conduit has been found in a small organ located in the nose—the vomeronasal organ, or VNO.
Let’s go back in time for a moment. The year is 1703 and a Dutch military surgeon identified in the literature as “Ruysch” is peering into what remains of the smashed and bloodied face of a wounded soldier. As Ruysch attempts to piece the soldier’s broken face into a recognizable whole, his eyes register a tiny slit inside the man’s nose, in the front portion of the nasal septum.
Further investigation by Ruysch reveals an identical pit lo-cated symmetrically on the other side of the nasal wall. The soldier’s nose contains two delicately ﬂeshy pits, but for what purpose? Fascinated by something he’d never before seen despite years of performing facial surgeries, Ruysch looked more closely. He documented his finding.
Ruysch’s description of the nasal feature caused little excitement and even Ruysch himself did not investigate it further. A century later, in 1811, Danish scientist Ludwig Levin Jacobson attached his own name to the pit, which he had seen in animals but not in humans. He called it jacobson’s organ, a name that has endured to this day in the world of animal science. In the early twentieth century scientists had, for the most part, concluded that the human vomeronasal organ existed in only a cautionary relic.
A vestigial structure or organ, such as the human appendix, is one that occurs or persists as a rudimentary or degenerate structure. This label seemed to seal the VNO’s fate until just a very small percentage of people and, when present, did not function. Convinced this was the case, writers of medical textbooks usually dismissed the human VNO as vestigial, an evolution.
The vomeronasal organ and then triggering the appropriate emotion or response.
Dr. David Berliner, president of the pheromone research company Pherin Pharmaceuticals, a biotechnologist and a former anatomy professor whose research on human pheromones is a key source for the information in this book, has taken the link between the VNO and the hypothalamus even further by testing ways to deliver drug therapies in the form of synthetic sub- stances acting on the VNO. In general, pheromone communication works like this: Messages taken into the VNO travel to the hypothalamus, reaching the brain in fractions of a second. Once at the emotional core of the brain, the message carried by the pheromone elicits the designated response. Thus, like animals responding to pheromonal cues as part of daily existence, we, too, react to pheromones without thinking.