A1, Androstadienone, or androsta-4,16,-dien-3-one

is a chemical that has shown strong pheromone-like behavior in humans. It is derived from progesterone and pregnenolone. Tests have shown that it can significantly influence the mood of heterosexual women and homosexual men.

Androstadienone is most commonly found in perspiration. It has also been found in the secretions of the human hair. ( School of Biosciences, Cardiff University, Cardiff CF10 3US, UK)

Androstadienone has shown gender specific reaction in women in particular activation of the hypothalamus Maximal activation was observed in the medial preoptic area/anterior hypothalamus, which, according to animal studies, is highly involved in sexual behavior, resulting in the female relaxing, slower breathing and heart rate. It has been demonstrated that women when exposed to Androstadienone let go of stress and discomfort followed by a feeling of well being. Multiple studies have shown this mood elevating reaction. It has also been said that it eases the symptoms of PMS as well as headaches in women.

Another study that was attempting to see if Androstadienone exposed women would be able to withstand greater levels of pain due to the relaxed Androstadienone induced state, discovered that exactly the opposite was true. Consequently, they accidentally demonstrated that Androstadienone increased the skin sensitivity of women due to a heightened state of arousal. (McGill Centre for Research on Pain, Strathcona Anatomy and Dentistry Building, 3640 University Street, Room M-19, Montreal, Que., Canada H3A 2B2. chantal.)

The above mentioned Androstadienone research demonstrates that exposure to A1 increases a women's sense of pleasure when being touched.

It has been demonstrated that women exposed to Androstadienone judge men as more attractive than when they have not been exposed. (School of Biological Sciences, University of Liverpool, Liverpool, L69 7ZB, UK)

For those who can smell Androstadienone it has a musky, woodsy, urine smell.

The above is only a small smattering of references to the overall research that has been done on Androstadienone