Testosterone treatment increases sexual desire and well-being in women with hypoactive sexual desire disorder; however, many studies have shown only modest benefits limited to moderate doses. Unlike men, available data indicate women show a bell-shaped dose-response curve for testosterone, wherein a threshold dosage of testosterone leads to desirable sexual function effects, but exceeding this threshold results in a lack of further positive sexual effects or may have a negative impact. Emotional and physical side-effects of excess testosterone, including aggression and virilization, may counteract the modest benefits on sexual interaction, providing a possible explanation for a threshold dose of testosterone in women. In this commentary, we will review and critically analyze data supporting a curvilinear dose-response relationship between testosterone treatment and sexual activity in women with low libido, and also explore possible explanations for this observed relationship. Understanding optimal dosing of testosterone unique to women may bring us one step closer to overcoming regulatory barriers in treating female sexual dysfunction.