Sex-hormone dependent perception of androstenone suggests its involvement in communicating competition and aggression.

Androstenone, a compound of human male body odor, might act as a chemosensory signal communicating dominance or aggressiveness. In order to clarify its communicative significance, the relationship between androstenone perception and the level of circulating steroid hormones was investigated in both men and women. Androstenone perception was assessed within n=26 men and n=25 women. Female participants were not currently using hormonal contraception and were in their follicular menstrual cycle phase. Androstenone perception was assessed in terms of olfactory sensitivity, quality judgments, and emotional self-ratings. The perception of isovaleric acid served as a control. Over the course of 2h five saliva samples were collected, aliquots were mixed and levels of estradiol and testosterone were analyzed via enzyme-linked immunosorbent assays. In men, higher testosterone levels were associated with lower olfactory sensitivity to androstenone (p=0.014) and negative feelings when exposed to it (p=0.047). In women, higher estradiol levels were related to judging androstenone as less pleasant (p=0.009) and more unpleasant (p=.0036). The perception of isovaleric acid was unrelated to sex-hormone levels. The current results support the notion of androstenone communicating dominance, aggression or competition. Men with higher testosterone levels are more sensitive to androstenone and dislike its odor, possibly indicating that androstenone signals the readiness for competition in men. Similarly, the fact that women with higher estradiol levels dislike androstenone may be due to androstenone being a signal of reduced willingness for social cooperation and an increased likelihood to engage in extramarital sex.