However, the risk associated with estrogens has led to search for alternatives such as selective estrogen receptor modulators, raloxifene, specific agonists for estrogen receptor subtypes (estrogen receptor α, estrogen receptor β, and membrane estrogen receptor GPER1).18 As reviewed above, androgen loss (due to aging or castration) and androgen treatment have not given solid beneficial or deleterious evidence in PD. Here, GPER1 is linked to Parkinson disease.