Does spironolactone for men block testosterone & causes impotence?

It can: This drug is a direct inhibitor of aldosterone, a hormone produced by the adrenal gland that is similar to a male hormone, which may be blocked partially by this drug, causing breast enlargement or erection problems. Women may have menstrual irregularities as well.

Common side effect: Spironolactone is considered a testosterone-blocker. While it is a blood pressure medication, it has side effects of breast development, decreased erections - particularly morning erections. Many transgender people use spironolactone as they are transitioning from male to female. LGromkoMD