Spironolactone is potassium-sparing diuretic that can also serve as an anti-androgen. It works as as antagonist by binding to Androgen Receptors and providing weak androgenic activity, blocking more potent androgens like Testosterone and DHT for binding to the receptor. Common effective doses are 100-200mg/day.

Spironolactone has been widely used particularly in the United States in transfeminine HRT since the 1980s, it is safe and well tolerated. Users should be careful to investigate side effects make sure they remain hydrated to due to its diuretic effects.