May 2018

Women Smell Better Than Men

Gender differences in smell function have been a topic of interest for many years. Some studies suggested that women had better smell acuity then did men whereas others could not determine this.

We studied 312 patients with smell loss (hyposmia) consisting of 178 women and 134 men to evaluate their hyposmia in response to treatment with oral theophylline. Prior to treatment there were no differences in smell function associated with the acuity loss as measured by olfactometry (precise psychophysical measurements of smell function).

As treatment with oral theophylline proceeded with increasing doses of the drug both men and women improved their smell function. However, smell function in women was relatively more sensitive than in men as the drug dose increased. On 200mg theophylline, although both men and women increased their olfactory acuity slightly, acuity was more sensitive in women than in men. On 400mg theophylline, with both men and women showing improved olfactory acuity, acuity was again more sensitive in women than in men but this was not statistically significant. On 600mg theophylline, with both men and women again showing improvement in their olfactory function, women now demonstrated increased sensitivity in their olfactory function than did men which was now statistically significantly different.

The mechanism by which this occurred is not yet clear. Theophylline levels in women were consistently higher than in men suggesting that they absorbed the drug better than did men and this may have allowed them to perceive odor better then did men. Based upon these increased blood levels of theophylline it is possible that women had a different metabolic clearance rate of theophylline than did men which allowed them to metabolize theophylline more efficiently then did men which led to their increased sensitivity for all odors.