Is dutasteride FDA-approved for hair loss?

No. AVODART, NDA 021319, is approved for symptomatic benign prostatic hyperplasia in men with an enlarged prostate, and the combination product JALYN pairs it with tamsulosin for the same condition. A DailyMed query returns 34 current dutasteride Structured Product Labels — the brand, the generics and the combinations — and every one of them is indicated for BPH. Prescribing it for hair is off-label: lawful for a physician, and it means the FDA has not evaluated the drug for that use, has not approved a dose for it, and has not reviewed any hair-loss claim made about it. Finasteride is the opposite case: PROPECIA at 1 mg is approved for exactly this.

Is dutasteride more effective than finasteride for hair?

In the one trial that randomised both, at 24 weeks, yes. Gubelin Harcha et al. enrolled 917 men aged 20 to 50 and reported that "Dutasteride 0.5 mg significantly increased hair count and width in a 2.54-cm diameter and improved hair growth (frontal view; panel photographic assessment) at week 24 compared with finasteride (P = .003, P = .004, and P = .002, respectively) and placebo (all P < .001)", with adverse events "similar among treatment groups". Read the caveats with the result: the trial ran 24 weeks, its own limitations section says so, and it was funded by the company that made AVODART. Twelve years later the US approval still does not exist, while Japan and South Korea have granted one.

What dose of dutasteride is used for hair loss?

No FDA label states one, and this page will not supply a figure from anywhere else. What can be reported is the trial: the arm that beat finasteride in Gubelin Harcha 2014 was dutasteride 0.5 mg daily, which is also the dose AVODART carries for benign prostatic hyperplasia and the dose Japan and South Korea approved for male AGA. Reporting what a trial gave is not the same as stating a dose. If a prescriber writes it for hair, the dose is their clinical judgement, and it is worth asking them what it is based on.

How long does each one take to leave the body?

Finasteride's label states a mean terminal half-life of 4.5 hours, range 3.3 to 13.4 hours. Dutasteride's states approximately 5 weeks at steady state, and adds that serum concentrations remain detectable above 0.1 ng/mL for up to 4 to 6 months after the last dose — with the half-life lengthening with age, from about 170 hours in men aged 20 to 49 to about 300 hours over 70. That is the practical difference between trying a drug and committing to one. It is also why the dutasteride label bars blood donation for six months after stopping and the finasteride label carries no such rule.

Do both of them mess up a PSA test?

Yes, and both labels tell you to plan for it. The PROPECIA label reports mean serum PSA falling from 0.7 ng/mL at baseline to 0.5 ng/mL at month 12 on 1 mg, and notes that PROSCAR at 5 mg roughly halves it. The AVODART label states that dutasteride "reduced serum PSA concentration by approximately 50% within 3 to 6 months of treatment" and instructs that a new baseline be set at least three months in, with any confirmed rise from it investigated "even if PSA levels are still within the normal range for men not taking a 5 alpha-reductase inhibitor". Tell whoever orders the test that you take it — the number means something different once you do.

Can I take both together?

Neither label describes combining them, no trial has tested the combination, and there is no reason to expect a benefit: dutasteride already inhibits both isoforms of the enzyme finasteride inhibits one of. Adding finasteride to dutasteride adds a second drug with the same class warnings and no additional target. If a protocol you have been shown includes both, it is worth asking what evidence it is based on, because none of it is on either label.

Head to head

Finasteride vs Dutasteride

Q: What dose of dutasteride is used for hair loss?

No FDA label states one, and this page will not supply a figure from anywhere else. What can be reported is the trial: the arm that beat finasteride in Gubelin Harcha 2014 was dutasteride 0.5 mg daily, which is also the dose AVODART carries for benign prostatic hyperplasia and the dose Japan and South Korea approved for male AGA. Reporting what a trial gave is not the same as stating a dose. If a prescriber writes it for hair, the dose is their clinical judgement, and it is worth asking them what it is based on.

Q: How long does each one take to leave the body?

Finasteride's label states a mean terminal half-life of 4.5 hours, range 3.3 to 13.4 hours. Dutasteride's states approximately 5 weeks at steady state, and adds that serum concentrations remain detectable above 0.1 ng/mL for up to 4 to 6 months after the last dose — with the half-life lengthening with age, from about 170 hours in men aged 20 to 49 to about 300 hours over 70. That is the practical difference between trying a drug and committing to one. It is also why the dutasteride label bars blood donation for six months after stopping and the finasteride label carries no such rule.

Q: Do both of them mess up a PSA test?

Yes, and both labels tell you to plan for it. The PROPECIA label reports mean serum PSA falling from 0.7 ng/mL at baseline to 0.5 ng/mL at month 12 on 1 mg, and notes that PROSCAR at 5 mg roughly halves it. The AVODART label states that dutasteride "reduced serum PSA concentration by approximately 50% within 3 to 6 months of treatment" and instructs that a new baseline be set at least three months in, with any confirmed rise from it investigated "even if PSA levels are still within the normal range for men not taking a 5 alpha-reductase inhibitor". Tell whoever orders the test that you take it — the number means something different once you do.

Q: Can I take both together?

Neither label describes combining them, no trial has tested the combination, and there is no reason to expect a benefit: dutasteride already inhibits both isoforms of the enzyme finasteride inhibits one of. Adding finasteride to dutasteride adds a second drug with the same class warnings and no additional target. If a protocol you have been shown includes both, it is worth asking what evidence it is based on, because none of it is on either label.

One of these has an FDA-approved hair-loss product. The other is a prostate drug used off-label. There is also a head-to-head trial, and it did not go the way the approvals did.

Reviewed September 2026

The short answer

Start with the thing that decides everything else: in the United States, finasteride has an approved hair-loss product and dutasteride does not. PROPECIA 1 mg is indicated "for the treatment of male pattern hair loss (androgenetic alopecia) in MEN ONLY". AVODART is a benign prostatic hyperplasia drug; a query of every current dutasteride label returns 34 of them and not one carries a hair indication. Using dutasteride for hair in the US is off-label prescribing — lawful for a physician, but it means no regulator has reviewed the drug for that use.

That is a regulatory fact, not a verdict on whether it works, and the distinction matters because the one head-to-head trial went the other way. 917 men were randomised to three doses of dutasteride, finasteride 1 mg or placebo for 24 weeks; dutasteride 0.5 mg significantly beat finasteride 1 mg on hair count and width and on the panel photographic assessment. Japan and South Korea have since approved dutasteride 0.5 mg daily for male AGA. The FDA has not, and no US dutasteride application carries that indication.

The second real difference is how long each one stays in you. Finasteride's label states a mean terminal half-life of 4.5 hours. Dutasteride's states approximately 5 weeks at steady state, with serum concentrations still detectable up to 4 to 6 months after the last capsule — which is why its label bars blood donation for six months afterwards and finasteride's label has no such rule. If a side effect appears, one drug is gone by tomorrow and the other is still there at Christmas.

Almost everything else is the same drug class behaving like the same drug class. Both suppress PSA and both labels tell you to re-baseline it. Both carry the high-grade prostate cancer warning — and the finasteride label cites the dutasteride trial when it does. Both are contraindicated in pregnancy and both labels make the dosage form itself the barrier against skin contact: the tablet coating for one, the capsule shell for the other.

2 of 15 dimensions are materially the same. They are marked below rather than dressed up as differences.

Finasteride

Propecia (1 mg) · Proscar (5 mg)

A type II 5α-reductase inhibitor. PROPECIA 1 mg is the only FDA-approved oral drug for male pattern hair loss.

Dosing protocol →

Dutasteride

Avodart · Jalyn (with tamsulosin)

Inhibits both the type 1 and type 2 isoforms. Approved in the US for benign prostatic hyperplasia only — hair loss is off-label.

Dosing protocol →

Side by side

Every row carries how well supported it is. A claim that only reflects common practice is labelled as such rather than presented as fact.

Dimension	Finasteride	Dutasteride	Basis
US indication	Male pattern hair loss (PROPECIA 1 mg); benign prostatic hyperplasia (PROSCAR 5 mg)	Symptomatic benign prostatic hyperplasia only	labelPROPECIA, verbatim: "indicated for the treatment of male pattern hair loss (androgenetic alopecia) in MEN ONLY. Efficacy in bitemporal recession has not been established." AVODART carries a BPH indication and no hair indication. This is the row the rest of the page hangs on.
Labelled dose for hair loss	1 mg once daily	None — the label states no hair-loss dose	labelPROPECIA, verbatim: "The recommended dose of PROPECIA is one tablet (1 mg) taken once daily." The 0.5 mg figure attached to dutasteride online is its BPH dose, read across to an indication its label does not carry. This page supplies no hair dose for dutasteride from anywhere else.
FDA application	NDA 020788 (Propecia), NDA 020180 (Proscar)	NDA 021319 (Avodart)	labelBoth are genuine approvals; they are approvals for different conditions. No US dutasteride application carries an androgenetic alopecia indication, and 34 current dutasteride SPLs on DailyMed are all indicated for BPH.
5α-reductase isoforms inhibited	Type II	Type 1 and type 2	labelAVODART, verbatim: "a selective inhibitor of both the type 1 and type 2 isoforms of steroid 5 alpha-reductase". Its own label notes that "the type 1 isoenzyme is also responsible for testosterone conversion in the skin", which is the pharmacological argument for using it on scalp — an argument, not an approval.
Serum DHT reduction	65% within 24 hours of a 1 mg tablet	94% at 1 year on 0.5 mg daily	labelThese are not the same measurement and must not be subtracted. Finasteride's figure is from men aged 18 to 41 at 24 hours; dutasteride's is the median in men with BPH after a year, from a label that also reports 85% at one week and 90% at two. No label reports the two on a common footing.
Terminal half-life	4.5 hours (range 3.3–13.4)	Approximately 5 weeks at steady state	labelRoughly 200-fold, and it governs everything downstream — the washout, the blood donation rule, and how long an unwanted effect takes to clear. Dutasteride's half-life also lengthens with age: about 170 hours at 20–49, 260 at 50–69, 300 over 70.
Detectable after stopping	Not stated on the label	Up to 4 to 6 months	labelAVODART, verbatim: "serum concentrations remain detectable (greater than 0.1 ng/mL) for up to 4 to 6 months after discontinuation of treatment." The PROPECIA label states no equivalent figure, so none is given here — a 4.5-hour half-life is not a washout period and this page will not convert one into the other.
Blood donation deferral	None on the label	At least 6 months after the last dose	labelAVODART, verbatim: "Men being treated with AVODART should not donate blood until at least 6 months have passed following their last dose." Its stated purpose is to keep dutasteride out of a pregnant transfusion recipient. A direct consequence of the half-life.
Effect on PSA	Mean 0.7 → 0.5 ng/mL at month 12 on 1 mg	Approximately 50% reduction within 3 to 6 months	labelBoth labels warn that a suppressed PSA read against the untreated reference range understates the true value, and both instruct that a new on-treatment baseline be established. AVODART goes further and tells clinicians to double an isolated on-treatment value for comparison. Tell whoever orders the test that you take it.
High-grade prostate cancer warningsame	Yes — PCPT, Gleason 8–10 in 1.8% vs 1.1% placebo	Yes — REDUCE, Gleason 8–10 in 1.0% vs 0.5% placebo	labelA class warning, and the finasteride label cites the dutasteride trial in making it: "Similar results were observed in a 4-year placebo-controlled clinical trial with another 5α-reductase inhibitor (dutasteride, AVODART)". Note the PCPT figure is from finasteride 5 mg, five times the hair-loss dose.
Pregnancy and handlingsame	Contraindicated; the tablet coating is the barrier	Contraindicated; the capsule shell is the barrier	labelBoth labels make the dosage form itself the protection. PROPECIA tablets "are coated and will prevent contact with the active ingredient during normal handling, provided that the tablets have not been broken or crushed." AVODART states "Dutasteride is absorbed through the skin". Break either and the protection is gone.
Dosage form	Film-coated tablet, oral once daily	Soft gelatin capsule with a liquid fill, oral once daily	labelFinasteride route, as its record states it: oral, once daily, with or without meals. Dutasteride: oral, once daily, swallowed whole and not chewed or opened. Neither has an FDA-approved topical form, whatever a compounding pharmacy is willing to make.
Head-to-head trial result	Comparator arm, 1 mg daily	Superior on hair count at 0.5 mg (P = .003)	literatureGubelin Harcha et al., J Am Acad Dermatol 2014: 917 men randomised to three dutasteride doses, finasteride 1 mg or placebo for 24 weeks. Dutasteride 0.5 mg beat finasteride on hair count, width and the panel photographic assessment. The paper's own limitation: "The study was limited to 24 weeks." GlaxoSmithKline-sponsored.
Approved for hair loss elsewhere	Widely, including the US	Japan and South Korea — not the US	literatureGupta, Talukder and Williams, J Dermatolog Treat 2022: "Recently, Japan and South Korea have approved oral dutasteride (0.5 mg/d) for male AGA." Everything else on this page is about the US label, and no other national register was searched.
How soon to judge it	Three months or more, per the label	Not stated for hair — no hair indication to state it for	labelPROPECIA, verbatim: "In general, daily use for three months or more is necessary before benefit is observed... Withdrawal of treatment leads to reversal of effect within 12 months." Both are maintenance therapy rather than a course, but only one label says so about hair.

label: Stated on the FDA label
guideline: Clinical practice guideline
literature: Published literature
practice: Common practice, not documented

Which one

Choose Finasteride if

You want the drug a regulator has actually reviewed for your condition. That is the whole case, and for most men it is enough.
You might want to stop quickly. A 4.5-hour half-life means a trial of finasteride is genuinely reversible in days; dutasteride is a four-to-six-month commitment the moment you swallow the first capsule.
You donate blood, or expect to. Only the dutasteride label defers you, and for six months.
Cost and access matter — the 1 mg product is generic, ubiquitous, and prescribed for hair by every telehealth platform in the category.

Choose Dutasteride if

Finasteride at 1 mg has been given a fair trial — the label says three months at minimum — and has not done enough. That is the usual reason a prescriber reaches for it.
You want the agent with the head-to-head result behind it, and you accept that the result is 24 weeks long, industry-sponsored, and did not lead to a US approval in the twelve years since.
You and your prescriber have talked through the half-life and you are comfortable that any unwanted effect will take months rather than days to clear.
You are also being treated for benign prostatic hyperplasia, which is the one indication dutasteride actually carries.

Both are 5α-reductase inhibitors and both carry the same class warnings: PSA suppression, the high-grade prostate cancer signal, and a categorical contraindication in pregnancy that makes the intact tablet or capsule the barrier. Neither is a cure and both are conditional on continuing — the finasteride label states plainly that "Withdrawal of treatment leads to reversal of effect within 12 months". The honest summary is that finasteride is the approved option and dutasteride is the off-label one with a better trial result and a much longer tail, and which of those two facts should weigh more is a conversation with a prescriber rather than something a web page can settle.

Frequently asked questions

Is dutasteride FDA-approved for hair loss?: No. AVODART, NDA 021319, is approved for symptomatic benign prostatic hyperplasia in men with an enlarged prostate, and the combination product JALYN pairs it with tamsulosin for the same condition. A DailyMed query returns 34 current dutasteride Structured Product Labels — the brand, the generics and the combinations — and every one of them is indicated for BPH. Prescribing it for hair is off-label: lawful for a physician, and it means the FDA has not evaluated the drug for that use, has not approved a dose for it, and has not reviewed any hair-loss claim made about it. Finasteride is the opposite case: PROPECIA at 1 mg is approved for exactly this.
Is dutasteride more effective than finasteride for hair?: In the one trial that randomised both, at 24 weeks, yes. Gubelin Harcha et al. enrolled 917 men aged 20 to 50 and reported that "Dutasteride 0.5 mg significantly increased hair count and width in a 2.54-cm diameter and improved hair growth (frontal view; panel photographic assessment) at week 24 compared with finasteride (P = .003, P = .004, and P = .002, respectively) and placebo (all P < .001)", with adverse events "similar among treatment groups". Read the caveats with the result: the trial ran 24 weeks, its own limitations section says so, and it was funded by the company that made AVODART. Twelve years later the US approval still does not exist, while Japan and South Korea have granted one.
What dose of dutasteride is used for hair loss?: No FDA label states one, and this page will not supply a figure from anywhere else. What can be reported is the trial: the arm that beat finasteride in Gubelin Harcha 2014 was dutasteride 0.5 mg daily, which is also the dose AVODART carries for benign prostatic hyperplasia and the dose Japan and South Korea approved for male AGA. Reporting what a trial gave is not the same as stating a dose. If a prescriber writes it for hair, the dose is their clinical judgement, and it is worth asking them what it is based on.
How long does each one take to leave the body?: Finasteride's label states a mean terminal half-life of 4.5 hours, range 3.3 to 13.4 hours. Dutasteride's states approximately 5 weeks at steady state, and adds that serum concentrations remain detectable above 0.1 ng/mL for up to 4 to 6 months after the last dose — with the half-life lengthening with age, from about 170 hours in men aged 20 to 49 to about 300 hours over 70. That is the practical difference between trying a drug and committing to one. It is also why the dutasteride label bars blood donation for six months after stopping and the finasteride label carries no such rule.
Do both of them mess up a PSA test?: Yes, and both labels tell you to plan for it. The PROPECIA label reports mean serum PSA falling from 0.7 ng/mL at baseline to 0.5 ng/mL at month 12 on 1 mg, and notes that PROSCAR at 5 mg roughly halves it. The AVODART label states that dutasteride "reduced serum PSA concentration by approximately 50% within 3 to 6 months of treatment" and instructs that a new baseline be set at least three months in, with any confirmed rise from it investigated "even if PSA levels are still within the normal range for men not taking a 5 alpha-reductase inhibitor". Tell whoever orders the test that you take it — the number means something different once you do.
Can I take both together?: Neither label describes combining them, no trial has tested the combination, and there is no reason to expect a benefit: dutasteride already inhibits both isoforms of the enzyme finasteride inhibits one of. Adding finasteride to dutasteride adds a second drug with the same class warnings and no additional target. If a protocol you have been shown includes both, it is worth asking what evidence it is based on, because none of it is on either label.

Sources

Next steps

Compare online hair loss providersWhich platforms prescribe which drug, what the consultation costs, and who will write dutasteride at all.Hair restoration: what the evidence supportsThe full ladder — topical, oral, procedural — and what each one is actually approved for.

Other comparisons

Educational reference, not medical advice. Which medication suits you is a decision for your prescriber.