estradiol is also important for dopamine neurons which produce dopamine.. if half of your dopamine neurons will die due to multiple e2 crashes your brain simply won't be able to produce enough dopamine so that causes one to be moody, sad, no drive and so on.. also increased risk for parkinson disease.. wouldnt wish this on anyone and unless you take dopamine drugs you can't get rid of that mood state it's permanent unless brain can create new dopamine producing neurons
gyno and water retention is walk in the park compared to what damage too low e2 does to humans especially to males.