Dutasteride vs finasteride for hair loss

Dutasteride and finasteride work the same way: both block 5-alpha reductase, the enzyme that turns testosterone into DHT, the hormone that shrinks follicles in male pattern hair loss. Dutasteride blocks both forms of the enzyme, finasteride only one, and in the largest head-to-head trial dutasteride grew more hair over 24 weeks.

The catch is approval. Finasteride 1 mg is FDA-approved for male pattern hair loss. Dutasteride is approved only for an enlarged prostate, so using it for hair loss in the US is off-label, and the dutasteride hair products sold online are compounded. Here is how they compare on evidence, safety and October 2026 price.

The two drugs side by side

The Gubelin Harcha trial calls finasteride a type 2 inhibitor and dutasteride a type 1 and 2 inhibitor. Blocking both forms lowers DHT further, which is the case for trying dutasteride when finasteride has not done enough.

What the trials show

Finasteride on its own

The finasteride label reports trials in 1,879 men aged 18 to 41. At 12 months, 14% of men on finasteride had further hair loss against 58% on placebo, and investigators rated hair growth as increased in 65% against 37%. Extensions ran to 5 years, when 35% on finasteride had further loss against 100% on placebo.

The head-to-head trial

The 2014 trial in the Journal of the American Academy of Dermatology randomly assigned 917 men aged 20 to 50 to dutasteride 0.02 mg, 0.1 mg or 0.5 mg a day, finasteride 1 mg a day, or placebo for 24 weeks. Three of its authors worked at GlaxoSmithKline research centers.

The low dutasteride doses (0.02 mg and 0.1 mg) did less, which matters because several compounded products use low or custom strengths. The authors noted the main limit: the trial lasted only 24 weeks, while hair loss treatment is lifelong.

Side effects and warnings

The two drugs share most of their warnings, because they act on the same hormone.

Finasteride has no boxed warning. Its label lists postmarketing reports of depression, suicidal ideation and behavior, and sexual problems that continued after stopping, plus male infertility and male breast cancer. In the first-year trials, decreased libido (1.8% vs 1.3%), erectile dysfunction (1.3% vs 0.7%) and ejaculation disorder (1.2% vs 0.7%) were a little more common than on placebo. Our finasteride side effects guide covers them in detail.

Dutasteride also has no boxed warning. Its label says:

• women who are or may be pregnant should not handle the capsules, because of the risk to a male fetus
• men should not donate blood until at least 6 months after the last dose
• it lowers PSA by about 50%, so a prostate screening result needs adjusting
• it may increase the risk of high-grade prostate cancer
• impotence, decreased libido, ejaculation disorders and breast disorders were reported more often than on placebo

Finasteride’s label carries the same high-grade prostate cancer warning for the class. The blood donation rule exists so that donated blood does not reach a pregnant woman.

Topical dutasteride is sold as a way to reduce body-wide exposure. No large trial has tested the compounded topical dutasteride products sold online, and they are not FDA-approved.

What to expect on either drug

Both drugs work slowly and only while you take them. The finasteride label says daily use for 3 months or more is usually needed before a benefit shows, continued use is needed to keep it, and the effect reverses within 12 months of stopping. It also notes that effectiveness for receding temples (bitemporal recession) has not been established; the trials measured the crown and the front-to-middle scalp.

The dutasteride trial ran for 24 weeks, so there is no long-term hair data for it from that study, and it is not known how long its advantage over finasteride lasts. Whichever you take, photograph your crown and hairline at the start and every few months, and give a treatment at least 6 to 12 months before judging it.

Many men also use minoxidil, which acts on the follicle rather than on DHT. See finasteride vs minoxidil.

Who each one suits

• Finasteride is the starting point for most men: approved for hair loss, studied for years and available as a low-cost generic.
• Dutasteride is a step a clinician may suggest when finasteride has not slowed loss enough after a fair trial. Finasteride usually takes 3 months or more to show a benefit, and its effect builds over the first year or two.
• Neither is for women who are or may be pregnant, who should not handle the tablets or capsules.

What each costs in October 2026

These are the published prices at the online providers we track, read on October 18, 2026. Every dutasteride hair product here is compounded.

Oral finasteride costs $17 to $55 a month at the providers that publish a price, counting regular rather than promotional prices, so dutasteride usually costs more. Strut Health is the lowest dutasteride price here and includes physician visits and shipping. Happy Head has dermatologists prescribe its capsules, and Maximus sells only the topical gel. See our cheapest finasteride list for finasteride prices, and the dutasteride page for label details.

The bottom line

Dutasteride blocks more DHT than finasteride and grew more hair over 24 weeks in a 917-man trial, with similar side effects. Finasteride is the one FDA-approved for hair loss, with years of data and a lower price. Dutasteride is off-label for hair, the products sold online are compounded, and its label asks you to wait 6 months after stopping before you donate blood.

If finasteride has not been enough, ask a licensed clinician whether dutasteride makes sense for you, and compare providers on our hair loss hub.