sexWomen who feel frisky may be recognizing, subconsciously, increased estrogen levels and optimal fertility, according to researchers. A new study published in Hormones and Behavior from researchers at the Department of Psychological and Brain Sciences in Santa Barbara claims elevated estrogen levels could spark increased desire for sexual behavior – or that feeling of wanting to get frisky.

The connection between sexual drive and reproductive hormone levels has long been considered. This study is one of the first to place factual measurements on reproductive levels that correlate those levels with the desire to be sexually active.

According to study researcher James Roney, two reproductive hormones come into play when it comes to sexual desire – estrogen and progesterone. Elevated estrogen levels caused increased libido while elevated progesterone levels caused decreased libido. Estrogen levels are higher during the most fertile days of a woman’s cycle, which could account for increased desire when estrogen levels spike. Progesterone, however, spikes at the end of the cycle when fertility is at its lowest, according to researchers. The spike in progesterone flips the switch on sexual desire, likely from a basic procreative level, because sex is the means of propagating the human species and if propagation chances are low sexual desire is not needed.

Undergraduate college women were used for the study, which only accounts for a small portion of the female reproductive population. Researchers believe results could be different in different age groups, particularly married women with a more regular menstrual cycle and consistent sex life.

One result of the study that is important to note was the lack of effect testosterone had on sexual desire. Researchers believe testosterone may be converted to estrogen in menopausal women, thus the increased libido. As estrogen increases so does libido, so testosterone may not be responsible for increased libido in menopausal women at all.

Future studies are needed across multiple age groups to determine natural cycle hormone/sexual desire variations among all women.

Source: James R. Roney, Zachary L. Simmons. Hormonal predictors of sexual motivation in natural menstrual cycles. Hormones and Behavior, 2013; 63 (4): 636 DOI: 10.1016/j.yhbeh.2013.02.013