Menstrual cycle phase and duration of oral contraception intake affect olfactory perception

Although a significant impact of cycle phase on olfactory thresholds has been shown in females, limited data exist regarding discrimination and identification. Therefore, we investigated a broader range of olfactory performance and analyzed the impact of cycle phase and oral contraception. We measured 80 healthy Caucasians, including 20 females taking oral contraceptives and 40 females without oral contraception who were further divided into follicular and luteal phase. Olfactory performance of all participants was assessed twice using the "Sniffin' Sticks" battery and intensity and pleasantness ratings of n-butanol were collected. Data analysis revealed that females outperformed males in odor discrimination and odor identification. In the luteal phase, higher thresholds and higher intensity ratings for n-butanol emerged. Duration of oral contraception correlated positively with olfactory performance pointing to better performance with longer intake. Hence, our data show that odor performance is affected by menstrual cycle phase and duration of oral contraception intake and thus can be modulated by hormonal changes.