Relapse levels and a decrease in estradiol levels during the luteal phase. Anxiety, irritability, and depression, three symptoms of both withdrawal and the human menstrual cycle, are most severe in the luteal phase. Symptoms of withdrawal not associated with the cycle, such as hunger, are also enhanced during the luteal phase, which suggests the role of estradiol and progesterone in enhancing symptoms above the naturally occurring level of the menstrual cycle. The symptoms of craving also increase during the luteal phase in humans (it is important to note that the opposite result occurs in female subjects with cocaine addiction suggesting that
Menstrual synchrony of the thawed axillary pad under their noses daily. The researchers concluded that odorless compounds collected from women during the late follicular phase of their menstrual cycles triggered hormonal events that shortened the menstrual cycles of the recipient women, and that odorless compounds collected from women during the time of ovulation triggered a hormonal event in the recipient women that lengthened their menstrual cycles. Stern and McClintock concluded that these findings "proved the existence of human pheromones" as well as illustrated manipulation of the human menstrual cycle. Researchers pointed out several flaws in their study. Whitten's main critiques was with