Not much is known about this type, but it is suggested that they act on genes in cells that produce neurotransmitters. Priming pheromones control hormone and neurotransmitter production in different areas of the brain. The effects of priming pheromones are evident in pregnant mice. Researchers have yet to decide if humans actually have pheromones, but most recent studies suggest that they do, in fact, exist in humans. This hypothesis is based on anatomical and physiological details in humans.
Apocrine glands give off proteins which bacteria use as their source of nutrition.
These bacteria then excrete their waste products, resulting in different odors. Recent studies have even discovered androstenone in human saliva, with higher concentrations detected in men's spittle than in that of women. Stephen Young and James Kohl refer to studies in which pheromones change reactions of women to men and vice versa. At Guy's Hospital in London, androstenol was sprayed in several telephone booths at the London train station. There are also bizarre cultural uses for human pheromones.