Propecia vs. Dutasteride

See how Propecia and Dutasteride compare on approved uses, dosing, side effects, and cost.

Key Takeaways

  • Propecia (finasteride) is FDA-approved specifically for male pattern hair loss, while dutasteride is FDA-approved for an enlarged prostate and used off-label for hair loss.

  • Both drugs lower DHT to slow hair loss, but dutasteride blocks two forms of the enzyme instead of one and tends to cause sexual side effects more often.

  • Generic dutasteride is typically far cheaper than Propecia, though Propecia has decades more safety data specifically for hair loss.

Propecia vs. Dutasteride Drug Summary

Propecia

Propecia (finasteride) is a 5-alpha-reductase inhibitor that treats male pattern hair loss in men by lowering DHT, the hormone that shrinks hair follicles. It's taken as a single 1 mg tablet once a day, and it's the only oral medication FDA-approved specifically for this use.

Dutasteride

Dutasteride is a 5-alpha-reductase inhibitor FDA-approved to treat an enlarged prostate (BPH), and it's commonly used off-label for male pattern hair loss. It's taken as a 0.5 mg capsule once a day and blocks both type 1 and type 2 of the enzyme that produces DHT.

Propecia vs. Dutasteride Side Effects

Propecia

Most common
decreased libido (up to 1.8%)
erectile dysfunction (up to 1.3%)
ejaculation disorder (up to 1%)
decreased ejaculate volume (up to 1.2%)

Dutasteride

Most common
decreased libido (up to 4%)
erectile dysfunction (up to 7.3%)
ejaculation disorder (up to 11%)
breast disorders (up to 2.2%)

Propecia vs. Dutasteride Dosage

Propecia

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 1 mg once daily At the start
Maximum dose 1 mg once daily Same as starting
Dose changes None Fixed dose

Dutasteride

Dosage
Dosage Table
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

Propecia vs. Dutasteride Indications

Propecia

Propecia is FDA-approved to treat androgenetic alopecia (male pattern hair loss) in men, and it's the only oral drug specifically indicated for this condition. It works by blocking the enzyme that converts testosterone into DHT, the hormone responsible for shrinking hair follicles in men prone to hair loss.

  • Treats male pattern hair loss (androgenetic alopecia) in men

  • Not approved for use in women

  • Not approved for pediatric patients

  • The only oral medication FDA-approved specifically for hair loss

Dutasteride

Dutasteride is FDA-approved to treat symptomatic benign prostatic hyperplasia (BPH), an enlarged prostate, either alone or combined with tamsulosin. It is not FDA-approved for hair loss, but many prescribers use it off-label for male pattern hair loss because it lowers DHT more completely than finasteride.

  • Treats symptomatic BPH (enlarged prostate) in men

  • Used with tamsulosin for BPH symptoms

  • Used off-label for male pattern hair loss

  • Not approved for prostate cancer prevention

Propecia vs. Dutasteride Pros and Cons

Propecia

Propecia has the longest track record of any oral treatment for hair loss and is the only one FDA-approved for that specific use. It blocks only one form of the DHT-producing enzyme, so its effect on DHT is less complete than dutasteride's, but it also carries a lower reported rate of sexual side effects.

Pros

  • Only oral medication FDA-approved specifically for male pattern hair loss

  • Lower reported rates of sexual side effects than dutasteride

  • Decades of safety data, having been FDA-approved since 1997

Cons

  • Blocks only type 2 5-alpha reductase, so DHT suppression is less complete than dutasteride's dual-enzyme action

  • Carries specific warnings for depression, suicidal thoughts, and persistent sexual side effects after stopping (post-finasteride syndrome)

  • Typically costs more per month than generic dutasteride (roughly $100 to $250 vs $8 to $40, before savings programs)

Dutasteride

Dutasteride blocks both forms of the DHT-producing enzyme, giving it a more thorough effect on DHT levels than Propecia. It's FDA-approved only for an enlarged prostate, so any use for hair loss is off-label, and it tends to cause sexual side effects more often than Propecia.

Pros

  • Generic version is widely available at low cost (roughly $8 to $40 vs $100 to $250 for Propecia, before savings programs)

  • Blocks both type 1 and type 2 5-alpha reductase for more complete DHT suppression

  • Also treats an enlarged prostate (BPH), which some men on it have alongside hair loss

Cons

  • Not FDA-approved for hair loss, so use for this purpose is off-label

  • Higher reported rates of sexual side effects, including erectile dysfunction in up to 7.3% of users

  • Long half-life keeps the drug detectable in the body for months after stopping, which matters for fertility planning

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