Finasteride vs. Dutasteride
See how Finasteride and Dutasteride compare on approved uses, dosing, side effects, and cost.
Key Takeaways
Finasteride is FDA-approved for both male pattern hair loss and BPH, while dutasteride is FDA-approved only for BPH and used off-label for hair loss.
Dutasteride blocks both type 1 and type 2 5-alpha-reductase, leading to stronger DHT suppression but higher rates of sexual side effects than finasteride.
Both drugs lower PSA levels and are unsafe for women who are pregnant or may become pregnant, including through skin contact with broken tablets or capsules.
Finasteride vs. Dutasteride Drug Summary
Finasteride
Finasteride is a 5-alpha-reductase inhibitor available as a low-dose 1 mg tablet for male pattern hair loss and a higher-dose 5 mg tablet for benign prostatic hyperplasia. It works by blocking the enzyme that converts testosterone into DHT and is taken once daily by mouth.
Dutasteride
Dutasteride is a 5-alpha-reductase inhibitor FDA-approved for benign prostatic hyperplasia, taken as a 0.5 mg capsule once daily. It is also widely prescribed off-label for male pattern hair loss because it blocks both forms of the 5-alpha-reductase enzyme.
Finasteride vs. Dutasteride Side Effects
Finasteride
Dutasteride
Finasteride vs. Dutasteride Dosage
Finasteride
Dutasteride
| 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 | 0.5 mg once daily | At the start |
| Maximum dose | 0.5 mg once daily | Same as starting |
| Dose changes | None | Fixed dose |
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 |
Dutasteride
| STAGE | DOSE | WHEN |
| Starting dose | 0.5 mg once daily | At the start |
| Maximum dose | 0.5 mg once daily | Same as starting |
| Dose changes | None | Fixed dose |
Finasteride vs. Dutasteride Indications
Finasteride
Finasteride is approved to treat male pattern hair loss at a 1 mg daily dose and symptoms of an enlarged prostate at a 5 mg daily dose. It works by lowering DHT, the hormone responsible for hair follicle shrinkage and prostate tissue growth. It is not approved for use in women or children.
Treats male pattern hair loss (1 mg dose)
Treats symptomatic BPH (5 mg dose)
Off-label use for hirsutism in women with hyperandrogenism
Not approved for women or children
No REMS program required
Dutasteride
Dutasteride is FDA-approved to treat symptomatic BPH, either alone or combined with tamsulosin. Off-label, it is widely prescribed for male pattern hair loss because it blocks both type 1 and type 2 5-alpha-reductase enzymes. It is not approved for use in women.
Treats symptomatic BPH (0.5 mg dose)
Combined with tamsulosin for BPH (Jalyn)
Off-label use for male pattern hair loss
Not approved for use in women
Blocks both types of 5-alpha-reductase
Finasteride vs. Dutasteride Pros and Cons
Finasteride
Finasteride has decades of use for hair loss with a well-established safety profile and broad availability as an affordable generic. Because it blocks only the type 2 5-alpha-reductase enzyme, it may cause somewhat fewer sexual side effects than dual inhibitors for some men. It also clears the body faster if side effects occur.
Pros
FDA-approved specifically for hair loss (Propecia)
Longer real-world track record (approved since 1992)
Clears the body faster, easing reversal of side effects
Generally lower rate of sexual side effects than dutasteride
Cons
Only partially blocks DHT (type 2 enzyme only)
May be less effective than dual inhibition for some men
Sexual side effects can persist after stopping
Two different dose strengths can cause product confusion
Dutasteride
Dutasteride blocks both type 1 and type 2 5-alpha-reductase, producing deeper and more complete DHT suppression than finasteride. This dual action may make it more effective for hair loss in some men, though that use remains off-label. Its long half-life means side effects and hormone changes can linger for months after stopping.
Pros
Blocks both types of 5-alpha-reductase for deeper DHT suppression
May work better than finasteride for some men with hair loss
Available combined with tamsulosin for BPH (Jalyn)
Long half-life may reduce impact of an occasional missed dose
Cons
Not FDA-approved for hair loss, only used off-label
Higher rates of sexual side effects than finasteride
Long half-life means effects linger for months after stopping
No dedicated FDA-approved product for hair loss dosing
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