**Abstract**

The clinical literature and recent studies in our laboratory using rodent models demonstrate that there are individual differences in androgens' pleiotropic effects across the lifespan that need to be better understood. The question to address that challenges the field is that levels of androgens (current and/or prior) may not drive differing responses to androgens. The clinical example of Post-finasteride Syndrome, in which side-effects persist long after treatment is discontinued, supports investigations of this novel question relating to long-term effects of androgen manipulations, independent of existing levels of androgens.

**Keywords:** steroids, neurosteroids, testosterone, 3a-Androstanediol, post-finasteride syndrome, traumatic brain injury
