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.

[1] 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.

Though it has been reported to significantly affect the mood of heterosexual women and homosexual men, it does not alter behavior overtly,[3][4][5][6] although it may have more subtle effects on attention.

[7] Androstadienone is commonly sold in male fragrances; it is purported to increase sexual attraction.

Androstadienone, in picogram quantities, has been shown to have "significant reduction of nervousness, tension and other negative feeling states" in female subjects.