Dutasteride and finasteride are close relatives. Both block the enzyme that turns testosterone into DHT, the hormone behind male pattern hair loss. Dutasteride blocks more of it, and some trials suggest it grows more hair. In the US, though, its use for this condition is off-label. This guide compares dutasteride and finasteride on how they work, efficacy, safety, regulatory status and cost, so you know what to ask a doctor.
This is general information, not medical advice. Last updated October 25, 2026.
Quick answer: dutasteride vs finasteride
- Mechanism: dutasteride inhibits type 1, 2 and 3 5α-reductase. Finasteride inhibits type 2 only.
- DHT reduction: dutasteride lowers serum DHT by more than 90%. Finasteride lowers it by about 70%.
- Efficacy: a 2019 meta-analysis and a 2024 systematic review both found dutasteride more effective for hair count.
- Safety: those same reviews found no significant difference in adverse events, though the trials were small and short.
- FDA status: finasteride 1 mg (Propecia) is labeled for male pattern hair loss. Dutasteride (Avodart) is labeled for BPH, so using it for hair loss is off-label.
How finasteride and dutasteride work
Finasteride and dutasteride are both 5α-reductase inhibitors. This enzyme converts testosterone into DHT, and DHT shrinks each susceptible hair follicle over time in androgenetic alopecia, which limits hair growth.
The difference is how many enzyme types each drug blocks. Finasteride is a type 2 inhibitor. Dutasteride inhibits types 1, 2 and 3. According to one clinic source, dutasteride is about 3 times as potent against type 2 and more than 100 times as potent against type 1. That broader action is why oral dutasteride lowers serum DHT by more than 90%, against about 70% for oral finasteride.
Half-life also differs. Finasteride's is roughly 6 to 8 hours. Dutasteride's is measured in weeks. Sources give about 4 to 5 weeks, and the exact figure should be confirmed on the FDA label. This matters when stopping dutasteride, because it stays in the body much longer.
What the trials show on hair count
Several pieces of evidence point the same way.
- 2019 meta-analysis: it pooled 3 trials with 576 men. Dutasteride gave better total hair count and better global photographic and self-assessment scores at 24 weeks. Sexual adverse events did not differ significantly.
- 2024 systematic review: covering male and female pattern hair loss, it found dutasteride at 0.5 mg and 2.5 mg significantly more effective than finasteride 1 mg for hair count, with no significant difference in adverse events.
- Randomized trial: an open-label, evaluator-blinded study reported that dutasteride was superior to finasteride in hair regrowth and reversal of miniaturization in men with androgenetic alopecia. The finasteride group did less well on both measures.
These findings have limits. The trials are few, mostly short (24 weeks) and the 2019 sample is small. I did not find a head-to-head trial running longer than a year. A clinic blog also cites a 2022 network meta-analysis ranking dutasteride higher, but that paper could not be confirmed, so treat it cautiously. In short trials dutasteride may look better than it does over years, and in a finasteride vs dutasteride choice, finasteride may still be the safer pick for some men.
Dosing
For hair loss, finasteride is taken as a 1 mg tablet daily. The label says benefit needs 3 months or more of daily use, so finasteride isn't a quick fix.
Dutasteride has no standard hair loss dose, which is expected for an off-label use. The 0.5 mg capsule is the BPH dose, and the 2024 review included studies at 0.5 mg and 2.5 mg. A doctor sets any dose for hair loss, and anyone planning to take dutasteride should ask about it directly.
FDA status and approvals
The FDA approved Propecia (finasteride 1 mg) in 1997 for male pattern hair loss in men only. Avodart (dutasteride) is FDA-approved for symptomatic BPH, including in combination with tamsulosin. Its label has no hair loss indication, so prescribing it for hair is off-label. Confirm this on Drugs@FDA, since I relied on the label as republished rather than the FDA page itself.
Dutasteride is approved in Japan and South Korea for this condition, according to a clinic source. That does not apply in the US.
Side effects and safety
The pooled reviews found no significant difference in adverse effects between the two drugs. Still, the finasteride label carries real warnings, and finasteride isn’t risk-free.
- Sexual effects: earlier Propecia trial data showed decreased libido in about 1.8% and erectile dysfunction in about 1.3%. The post-marketing list includes sexual dysfunction that continued after stopping.
- Mood: depression was added to the label in 2011. In 2022 the FDA required suicidal ideation and behavior to be added. News reports say the agency has received more than 700 reports of suicide or suicidal thoughts with finasteride.
- The causation debate: advocacy groups argue for a causal link with persistent problems, sometimes called post-finasteride syndrome. Per one advocacy summary, the FDA said a citizen petition did not provide reasonable evidence of a causal link to persistent sexual problems, depression or suicide. Anyone taking finasteride who notices mood changes should tell a doctor, and a doctor can advise whether to stop finasteride.
- Pregnancy: finasteride is contraindicated in pregnancy because of a risk of abnormal external genitalia in a male fetus. Women who are or may be pregnant should not handle crushed or broken tablets.
For dutasteride, labels say not to donate blood until 6 months after the last dose. Dutasteride also lowers PSA by about 50% within 3 to 6 months, and any confirmed PSA rise on therapy should be evaluated. In the 4-year REDUCE trial in men at prostate cancer risk, Gleason 8 to 10 prostate cancer occurred in 1.0% on dutasteride versus 0.5% on placebo, and the label notes a similar finasteride trial showed the same direction. Dutasteride use therefore calls for PSA awareness, and finasteride treatment does too.
I did not find dutasteride-specific persistent sexual or psychiatric label language for hair loss use, or a long-term head-to-head safety comparison. Report suspected side effects to your doctor, and ask them about reporting options with the FDA.
Cost in the US
Both generics are inexpensive, though prices vary and these figures are undated, so recheck them.
- GoodRx lists generic finasteride from $8.99 for 30 days with a coupon, and generic dutasteride from $12.00. That page is about BPH, so the finasteride price may be for 5 mg, not the 1 mg hair loss tablet.
- Another site puts generic dutasteride at about $8 to $12 at Costco and $12 to $18 at Walmart and Kroger for 30 capsules.
- Brand Avodart can be as low as $5 a month with the manufacturer copay card for commercially insured patients.
Because the hair loss use of dutasteride is off-label, I found no information on insurance coverage for it.
Is dutasteride right for you?
Finasteride has the on-label status and the longer track record in hair loss. Dutasteride has stronger DHT suppression and better results in short trials, but off-label status and a long half-life. A reasonable conversation with a doctor covers:
- Whether finasteride has worked for you, and for how long you have been taking it
- Your history of sexual or mood side effects
- Whether you plan to father a child or live with someone who may be pregnant
- Whether you may need PSA monitoring or plan to donate blood
Neither drug is the only route. If medication alone is not enough, our guides to FUE hair transplants and PRP hair restoration cover other options.
Frequently Asked Questions
Is dutasteride more effective than finasteride for hair loss?
In the studies reviewed here, yes for hair count. A 2019 meta-analysis and a 2024 systematic review found dutasteride better. The trials were few and short, so longer head-to-head data is still needed.
Is dutasteride FDA-approved for hair loss?
No. Avodart is approved for BPH, so hair loss use is off-label. Finasteride 1 mg (Propecia) is labeled for male pattern hair loss.
Does dutasteride have fewer side effects than finasteride?
No. The reviews found no significant difference in adverse events between the two drugs.
How long does finasteride take to work?
The label says benefit needs 3 months or more of daily use.
Can women take finasteride or dutasteride?
Propecia is labeled for men only. Finasteride is contraindicated in pregnancy. Women who may be pregnant should not handle crushed or broken tablets. Talk to a doctor about any use in women.
What happens if I stop dutasteride?
Its half-life of about 4 to 5 weeks means it stays in the body far longer than finasteride. Ask your doctor what to expect before you stop.