The relationship between human sexuality and androgens is complex and still not well understood. In 1970, an anonymous researcher published a case study in Nature
in which he demonstrated that anticipation of sexual activity could increase testosterone levels in men, as measured indirectly by beard growth. Over the course of two years, the researcher spent periods of several weeks conducting research in isolation. He began weighing his beard clippings once daily as an androgen bioassay. On days when he was anticipating visiting his female sexual partner and on days immediately following sexual activity, his beard clippings were heavier, indicating higher levels of androgen production (Anonymous, 1970
). This interesting case study led to a series of more controlled studies on the relation between sexual activity with a partner, partner presence, and androgens, particularly testosterone.
Several studies done in male rodents have shown that testosterone increases in anticipation of sexual activity (e.g. Graham & Desjardins, 1980
), in the presence of a receptive female (e.g. Bonilla-Jaime et al., 2006
) and in response to copulation (Kamel et al., 1975
, Bonilla-Jaime et al., 2006
). In studies of the effects of sexual activity on testosterone in human males, results have been varied. One early case study conducted with a male participant found that testosterone was higher in blood samples taken during (pre-orgasm) and after (post-orgasm) intercourse compared to control samples taken on non-sex days. There was no significant difference between pre- and post-orgasm samples, however (Fox et al., 1972
). Two subsequent studies also found that testosterone was higher on nights when sex occurred (Dabbs & Mohammed, 1992
= 4) and the morning after sex occurred (Kraemer et al., 1976
= 20), compared to non-sex days. In contrast, two studies with eight and six male participants, respectively, found no increase in testosterone related to sexual intercourse (Lee et al., 1974
, Stearns et al., 1973
). All of the above studies on sexual intercourse used discrete sampling methods and, with the exception of Dabbs and Mohammed (1992)
who sampled saliva, all of the studies examined plasma testosterone. For reviews on the effects of sexual activity and testosterone on men see Archer (2006)
and van Anders and Watson (2006)
To our knowledge, there have been no studies of androgen responses to sexual activity in non-human females. Testosterone only seems to play a role in female sexual behavior when the behavior is decoupled from the estrous cycle (e.g., Rissman, 1995
), although it has been argued that any effect of increased testosterone on female sexual motivation and behavior is a result of its aromatization to estradiol (e.g., Wallen, 2001
). Studies of women’s testosterone responses to sexual activity have also shown variable results (for a review see van Anders & Watson, 2006
). Using discrete sampling methods, three studies have looked at women’s testosterone levels in relation to sexual intercourse. One study found no change in plasma levels of testosterone after sexual intercourse (Lee et al., 1974
), and two subsequent studies found testosterone increased around times of sexual activity. Of the two studies that noted increases, one found higher testosterone levels in a small sample of four women on nights when sex occurred compared to non-sex nights (Dabbs and Mohammed, 1992
). In a larger sample of 16 women, van Anders et al. (2007)
found testosterone was higher both before and after sexual intercourse compared to nights where the women engaged in control activities, providing evidence for both an anticipatory increase in testosterone and an overall elevation in testosterone with sexual activity. This study also compared women who did and did not have orgasms during sexual activity and found that women who experienced orgasms had higher overall testosterone the day of the sexual activity.
If there is an effect of sexual activity on testosterone in women, we expect that it will be most pronounced after a period of abstinence from sexual activity with a partner. Exton et al. (2001)
found that when men masturbated after 3 weeks of abstinence from all sexual activity, their testosterone was higher than when masturbating during a non-abstinence period. Baseline testosterone was not different for the abstinence and non-abstinence conditions. Another study on abstinence found that when testosterone was measured daily, it was stable over the course of 8–16 days of abstinence, with the exception of a spike seven days following last ejaculation (Jiang et al., 2003
Several animal studies have shown that being separated from a partner results in increased cortisol or corticosterone levels when compared to being separated from a sibling (prairie voles: Bosch et al., 2009
) or even an infant (titi monkeys: Mendoza et al., 1986
). The social isolation/partner separation paradigm used in animal research may be somewhat limited in its generalizability to humans, however, given that it is more analogous to being placed in solitary confinement. In studies of human partner separation, participants often have phone or email contact with their partners as well as other social contacts. A more relevant study of partner separation, conducted with human subjects, found that cortisol did not change in response to separation for people low in attachment anxiety, but people high in attachment anxiety showed increased cortisol in response to separation. Cortisol was lower for the high anxiety group both in preparation for separation and upon reunion and was highest while they were actually separated from their partners (Diamond et al., 2008
). There is some evidence of an inverse relationship between cortisol and testosterone under conditions of stress (e.g. Cummings et al., 1983
; for a review see Rivier & Rivest, 1991
), so high cortisol could be linked with lower testosterone during separation.
Another study of partner separation looked at testosterone levels in couples who were in long distance or same-city relationships, as well as single people. Women in same city relationships had lower testosterone levels compared to single women, while those in long distance relationships were not significantly different from single women (van Anders & Watson, 2007
). These findings suggest that women separated from their partners have higher basal testosterone than those in same-city relationships. We do not know how basal levels of testosterone may change in response to partner presence and sexual activity in women.
Several researchers have demonstrated that exposure to putative male pheromones can have an effect on women’s physiological (e.g., Jacob et al., 2001
) and endocrine responses (e.g. Preti et al., 2003
; Wyart et al., 2007
). Other pheromonal research has demonstrated that being exposed to male sweat extract can alter menstrual cycle length in women (e.g., Cutler et al., 1986
). These studies show that pheromonal or odor cues from being exposed to males can have an effect on a woman’s own physiology, which could be one possible mechanism that can explain any change in women’s testosterone levels. Of course, if there is a change before the woman is reunited with her partner, then the mechanism is likely to be rooted in changes resulting from changes in her psychological state.
The present study is an attempt to further explore the changes in testosterone that occur from being with a sexual and romantic partner. Specifically, we were interested in both the effects of partner presence and sexual activity after a period of separation on testosterone levels. We recruited women who were in long distance relationships, and whose partners visited for brief periods of time. Because past research suggests testosterone is highest on days when sexual activity occurs (van Anders et al., 2007
), but does not necessarily change over the course of sexual activity (Lee et al, 1974
), we sampled on specific days as opposed to immediately before and after intercourse. We hypothesized that, compared to when they were alone, salivary testosterone levels would be highest the day before seeing a partner as seen in Anonymous (1970)
and throughout the visit, which would include sexual intercourse. We predicted testosterone would be lowest during the initial period of separation and after the visit.