Does spironolactone cause hair loss?

Spironolactone is actually a potassium-sparing diuretic but it's anti-androgen effect can counter the hormones that promote the development of acne and also can help women who experience hair loss due to higher levels of androgens. 

Spironolactone is an anti androgen type medication which is helpful for a proportion of women with androgenetic alopecia (sometimes called female pattern hair loss). Spironolactone can help women with BOTH normal androgen levels and increased androgen levels.  If a person does not have female pattern hair loss, or has some other type of hair loss, this medication will not be helpful. Common side effects include dizziness, frequent urination in the first few weeks, mood changes, breast tenderness, breast enlargement, decreased libido, irregular periods. Women using spironolactone must not get pregnant as it could harm the developing baby. Electrolyte abnormalities are rare on this medication. But yes, there are three common uses of spironolactone as off label treatments:treatment of hair loss (androgenetic alopecia) in womentreatment of acne in womentreatment of excess hair on the face in women (hirsuitism)

Spironolactone is
one of the medicines that is sometimes used to treat female pattern hair loss.
Hair loss is not one of the common side effects from this medicine – blood
pressure (hypotension) and electrolyte changes are the most common things that
can occur with it and are checked regularly when someone is put on
spironolactone.