Human pheromones

Androsterone, or 3α-hydroxy-5α-androstan-17-one, is an endogenous steroid hormone, neurosteroid, and putative pheromone. It is a weak androgen with a potency that is approximately 1/7 that of testosterone. Androsterone is a metabolite of testosterone and dihydrotestosterone (DHT). In addition, it can be converted back into DHT via 3α-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase, bypassing conventional intermediates such as androstanedione and testosterone, and as such, can be considered to be a metabolic intermediate in its own right.

Androstenone (5α-androst-16-en-3-one) is a 16-androstene class steroidal pheromone. It is found in boar's saliva, celery cytoplasm, and truffle fungus. Androstenone was the first mammalian pheromone to be identified. It is found in high concentrations in the saliva of male pigs, and, when inhaled by a female pig that is in heat, results in the female assuming the mating stance. Androstenone is the active ingredient in 'Boarmate', a commercial product made by DuPont sold to pig farmers to test sows for timing of artificial insemination.

Androstadienone, or androsta-4,16-dien-3-one, is a 16-androstene class endogenous steroid that has been described as having potent pheromone-like activities in humans. The compound is synthesized from androstadienol by 3β-hydroxysteroid dehydrogenase, and can be converted into androstenone (a more potent and odorous pheromone) by 5α-reductase, which can subsequently be converted into 3α-androstenol or 3β-androstenol (also more potent and odorous pheromones) by 3-ketosteroid reductase.

Androstenol, also known as 5α-androst-16-en-3α-ol (shortened to 3α,5α-androstenol or 3α-androstenol), is a 16-androstene class steroidal pheromone and neurosteroid in humans and other mammals, notably pigs. It possesses a characteristic musk-like odor.

Estratetraenol, also known as estra-1,3,5(10),16-tetraen-3-ol, is an endogenous steroid found in women that has been described as having pheromone-like activities in primates, including humans. Estratetraenol is synthesized from androstadienone by aromatase likely in the ovaries, and is related to the estrogen sex hormones, yet has no known estrogenic effects. It was first identified from the urine of pregnant women.