Inclusion Criteria:

• Female, age 18-75
• Written informed consent
• Meet DSM-IV criteria (by SCID) for Major Depressive Disorder
• Meet DSM-IV criteria for a current major depressive episode, as assessed by SCID
• MADRS > or = 16 at baseline visit
• Currently treated with SSRI or SNRI, with or without adjunctive therapy, at an adequate dose (see adequate dose table below) for at least six weeks

Exclusion Criteria:

• Pregnant women or women of child bearing potential who are not using a medically accepted means of contraception (to include oral contraceptive or implant, condom, diaphragm, spermicide, intrauterine device, tubal ligation, or partner with vasectomy)
• Serious suicide or homicide risk, as assessed by evaluating clinician
• Unstable medical illness including cardiovascular, hepatic, renal, respiratory, endocrine, neurologic (including uncontrolled seizure disorder)
• Substance use disorder active within last six months
• Psychotic features (current episode or lifetime), as assessed by SCID
• Laboratory evidence of untreated hypothyroidism
• If treated hypothyroidism, significant change in levo-thyroxine dose within the prior three months
• If receiving oral estrogen therapy, including oral contraceptives or transdermal estrogen therapy, significant change in dose in the prior three months
• Use of androgens or androgen precursors, including testosterone, DHEA and methyltestosterone, within the prior three months
• Any investigational psychotropic drug within the last two weeks
• In the judgment of the study clinician, unlikely to be able to participate safely throughout the study period (three or more episodes of self-harm in the past year, documented history of poor treatment adherence, or frequent missed appointments (>50%) in the past year)
• Alanine aminotransferase (ALT) > 1.5x upper limit of normal.
• Creatinine > 1.5x upper limit of normal
• History of a hormone-responsive cancer
• History of congestive heart failure
• MADRS > 31