TLDR Spironolactone is better than placebo for reducing excessive hair growth in women, but its effectiveness for acne is unclear due to small study sizes.
The review aimed to evaluate the effectiveness of spironolactone, alone or in combination with steroids, in treating hirsutism and acne in women. Seven small randomized controlled trials with no more than 41 participants each were included. The review found that 100 mg/day of spironolactone significantly improved hair growth and reduced Ferriman-Gallwey scores when compared to placebo. Additionally, spironolactone was superior to finasteride 5 mg/day and low-dose cyproterone acetate 12.5 mg/day in maintaining these improvements up to 12 months after treatment ended. However, the effectiveness of spironolactone for acne could not be determined due to the small sample sizes of the trials. The wide confidence intervals and small sample populations limit the confidence in these findings, making it difficult to assess the clinical value of spironolactone for these conditions based on the available research.
78 citations,
October 2003 in “Cochrane library” Cyproterone acetate with estradiol may subjectively improve excessive hair growth in women, but it's not clinically better than other treatments.
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56 citations,
April 2003 in “Fertility and Sterility” All three treatments reduce hirsutism, but spironolactone works best long-term.
12 citations,
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46 citations,
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23 citations,
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16 citations,
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44 citations,
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[object Object] 142 citations,
February 1985 in “Fertility and sterility” Spironolactone reduced hair thickness and some testosterone levels in women with excessive hair growth.
3 citations,
November 2013 in “PubMed” 
85 citations,
June 2006 in “Best Practice & Research Clinical Endocrinology & Metabolism” The document concludes that hirsutism is the main sign for diagnosing hyperandrogenism, which requires a detailed patient history and physical exam.
[object Object] 124 citations,
September 1980 in “The Journal of clinical endocrinology and metabolism/Journal of clinical endocrinology & metabolism” Spironolactone is effective in treating excessive hair growth in women.
