Four clinical trials with E2 have been performed among post-menopausal women with PD [91-94]. These studies reported positive results on symptomatic endpoints, but did not measure neuroprotection.
Overall, the majority of E2 studies showed promising neuroprotective properties in vivo. Furthermore, the association between a lower risk of PD and women appears to indicate that E2 is a promising compound. Unfortunately, no attention has been paid to the effects of E2 in paraquat and rotenone models; thus, future research should focus on these models.