Finasteride vs. Spironolactone
See how Finasteride and Spironolactone compare on approved uses, dosing, side effects, and cost.
Key Takeaways
Finasteride is FDA-approved for male pattern hair loss and BPH in men, while spironolactone's use for hair loss is entirely off-label.
Spironolactone is mainly used off-label for female pattern hair loss, hirsutism, and acne, since it is FDA-approved only for blood pressure, heart failure, and fluid retention.
Finasteride's main side effects involve sexual function, while spironolactone's main side effects involve hormone-related changes like menstrual irregularity and breast tenderness.
Finasteride vs. Spironolactone Drug Summary
Finasteride
Finasteride is a 5-alpha-reductase inhibitor FDA-approved to treat male pattern hair loss and benign prostatic hyperplasia (BPH) in men. It comes as a once-daily oral tablet, with a 1 mg dose used for hair loss and a 5 mg dose used for BPH.
Spironolactone
Spironolactone is a potassium-sparing diuretic and androgen blocker FDA-approved for high blood pressure, heart failure, and fluid retention. It is taken as a once-daily oral tablet, and dermatologists also prescribe it off-label for female pattern hair loss, hirsutism, and acne.
Finasteride vs. Spironolactone Side Effects
Finasteride
Spironolactone
Finasteride vs. Spironolactone Dosage
Finasteride
Spironolactone
| STAGE | DOSE | WHEN |
| Starting dose | 1 mg once daily | At the start |
| Maximum dose | 5 mg once daily | If needed |
| Dose changes | 1 increase | As tolerated |
| STAGE | DOSE | WHEN |
| Starting dose | 50 mg once daily | Weeks 1-2 |
| Maximum dose | 100-200 mg once daily | If needed |
| Dose changes | 2 increases | As tolerated |
Finasteride
| STAGE | DOSE | WHEN |
| Starting dose | 1 mg once daily | At the start |
| Maximum dose | 5 mg once daily | If needed |
| Dose changes | 1 increase | As tolerated |
Spironolactone
| STAGE | DOSE | WHEN |
| Starting dose | 50 mg once daily | Weeks 1-2 |
| Maximum dose | 100-200 mg once daily | If needed |
| Dose changes | 2 increases | As tolerated |
Finasteride vs. Spironolactone Indications
Finasteride
Finasteride is FDA-approved to treat androgenetic alopecia (pattern hair loss) in men and to shrink an enlarged prostate in men with BPH. It works by blocking the conversion of testosterone to DHT, the hormone most responsible for hair follicle shrinkage and prostate growth. It is also used off-label to treat hirsutism in women with excess androgen levels.
Male pattern hair loss (androgenetic alopecia) in men - FDA-approved
Benign prostatic hyperplasia (enlarged prostate) in men - FDA-approved
Hirsutism in women with excess androgens - off-label
Not approved for use in women or in children
Spironolactone
Spironolactone is FDA-approved for high blood pressure, heart failure, and fluid buildup caused by heart, liver, or kidney disease, and to help diagnose and treat primary hyperaldosteronism. It is not FDA-approved for hair loss, but dermatologists commonly prescribe it off-label to treat female pattern hair loss along with hirsutism and hormonal acne.
Heart failure (NYHA class III-IV) - FDA-approved
Resistant hypertension, as add-on therapy - FDA-approved
Edema from heart, liver, or kidney disease - FDA-approved
Female pattern hair loss, hirsutism, acne - off-label
Finasteride vs. Spironolactone Pros and Cons
Finasteride
Finasteride has a long track record specifically for male hair loss, with FDA approval since 1992 and decades of trial data behind it. Coverage for the hair loss indication is often out-of-pocket since insurers tend to treat it as cosmetic.
Pros
FDA-approved specifically for male pattern hair loss, backed by large trials
Once-daily pill with more than 30 years of established safety data
Targets DHT directly with minimal effect on blood pressure or electrolytes
Widely available as a low-cost generic tablet
Cons
Only approved for use in men; women who are or may become pregnant should not handle it
Sexual side effects like low libido can persist after stopping the drug
Does not treat hirsutism or acne the way spironolactone can
Can lower PSA levels, which may complicate prostate cancer screening
Spironolactone
Spironolactone brings decades of cardiovascular safety data to an off-label role in hair loss, making it a familiar option for prescribers despite lacking approval for that use. Insurance usually covers it readily for its approved indications, though coverage specifically for hair loss can vary.
Pros
Off-label option for female pattern hair loss that also treats hirsutism and acne
More than 60 years of clinical use, mostly for blood pressure and heart failure
Flexible tablet strengths allow gradual dose titration to balance effect and tolerability
Can be paired with oral contraceptives to manage menstrual side effects
Cons
Not FDA-approved for any form of hair loss; all hair-related use is off-label
Requires periodic blood tests to check potassium and kidney function
Menstrual irregularities are common at the doses used for hair loss
Breast tenderness and other feminizing effects make it unsuitable for most men
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