Finasteride Results: What the Trials Report by Timepoint

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Short answer: Finasteride 1 mg, sold as Propecia, is a prescription hair loss treatment, and the before and after numbers below come from the Propecia trials. The prescribing information says daily use “for three months or more is necessary before benefit is observed.” In its two vertex trials, men taking finasteride 1 mg had 107 more hairs than men on placebo in a 1-inch circle at 1 year, 138 more at 2 years and 277 more at 5 years. It also says stopping leads to reversal of effect within 12 months (Propecia prescribing information).

This page lays out what the Propecia trials and later follow-up studies measured at each timepoint, from 3 months to 10 years, and what happened when men stopped. It reports numbers only; it has no before and after photos.

How long does finasteride take to work?

Finasteride 1 mg is sold as Propecia, a tablet taken by mouth. Its prescribing information says that, in general, daily use for three months or more is necessary before benefit is observed. In the trials, men’s own ratings of their hair showed improvement over placebo “as early as 3 months” (p<0.05), and that difference held through 5 years. Hair counts were significantly higher than placebo at 6 and 12 months (Propecia prescribing information).

The trials enrolled 1,879 men aged 18 to 41 with mild to moderate hair loss across three 12-month studies: two vertex (crown) studies with 1,553 men and one anterior mid-scalp study with 326 men (Propecia prescribing information). For background on the drug itself, see our guide to finasteride for hair loss.

Finasteride results by timepoint

The table lists what the Propecia prescribing information reports at each timepoint for the vertex studies. “Hair count” is the difference from placebo in a 1-inch circle on the crown.

Timepoint	What was measured	Finasteride 1 mg	Placebo
3 months	Men’s self-assessment	Improvement over placebo (p<0.05)	Comparison group
6 months	Hair count	Significant increase vs placebo (no number given)	Comparison group
1 year	Hair count difference	107 more hairs (679 men)	672 men
1 year	Photo panel: increase	48%	7%
1 year	Investigator: increased hair growth	65%	37%
2 years	Hair count difference	138 more hairs (433 men)	47 men
2 years	Photo panel: increase	66%	7%
2 years	Investigator: increased hair growth	80%	47%
5 years	Hair count difference	277 more hairs (219 men)	15 men
5 years	Investigator: increased hair growth	77%	15%

Source: Propecia prescribing information, section 14. All hair count differences were reported at p<0.001. Later timepoints had far fewer placebo men (see the limits section below).

Year 1

Kaufman and colleagues published the two vertex trials. The 1,553 men started with an average of 876 hairs in a 1-inch circle on the balding crown. At 1 year, the finasteride group had 107 more hairs than placebo (P<.001), and the authors reported that the placebo group had progressive hair loss (Kaufman et al., 1998).

Year 2

In the blinded extension, 1,215 men continued. At 2 years the difference was 138 hairs (P<.001) (Kaufman et al., 1998). The Propecia prescribing information reports that 66% of finasteride men were rated as having an increase on photos at 2 years, versus 7% on placebo (Propecia prescribing information).

Year 5

The study group ran up to four more 1-year placebo-controlled extensions. Their 5-year report says finasteride showed significant differences from placebo on all endpoints, with progressive hair loss in the placebo group (Finasteride Male Pattern Hair Loss Study Group, 2002). The Propecia prescribing information gives the 5-year photo results:

5-year photo assessment	Finasteride 1 mg	Placebo
Increase in hair	48%	6%
No change	42%	19%
Hair loss	10%	75%

Source: Propecia prescribing information.

Beyond 5 years

Rossi and colleagues followed 118 men aged 20 to 61 taking finasteride 1 mg a day for 10 years, scoring standardized photos at 1, 2, 5 and 10 years. The study had no placebo group. The authors reported that 42.8% of men aged 20 to 30 did not improve even after 10 years, that 58.9% of men with grade IV and 45.4% with grade V hair loss had their first improvement only after 1 year, and that 6% reported side effects (Rossi et al., 2011).

What does “before and after” mean in the trials?

The trials used three kinds of measures (Propecia prescribing information):

• Hair counts: hairs counted in the same 1-inch circle on the scalp at each visit.
• Photo assessment: an expert review of scalp photographs rated hair as increased, unchanged or decreased.
• Investigator and patient ratings: the study doctor and each man rated the change.

So a trial “after” is a count or a rating, not a single photo. In the 5-year photo results in the prescribing information, 10% of men on finasteride were rated as having hair loss.

Does finasteride work on the hairline?

The Propecia prescribing information reports that the 326-man anterior mid-scalp study “also demonstrated significant increases in hair count compared with placebo.” It does not give the numbers in the summary, and it says those hair counts “did not include the area of bitemporal recession or the anterior hairline,” so the prescribing information does not report hairline results (Propecia prescribing information).

What happens if you stop finasteride?

In the trials, 48 men who took finasteride for 1 year were switched to placebo. The prescribing information says this “resulted in reversal of the increase in hair count 12 months later, at 24 months.” It also states that “Withdrawal of treatment leads to reversal of effect within 12 months” (Propecia prescribing information).

What are the limits of these results?

• The Propecia trials enrolled only men aged 18 to 41 with mild to moderate hair loss (Propecia prescribing information).
• The placebo groups at later timepoints were small: 47 men at 2 years and 15 men at 5 years, against 433 and 219 men on finasteride (Propecia prescribing information).
• The 10-year study had no placebo group, and its authors describe it as uncontrolled (Rossi et al., 2011).
• Hair counts and photo ratings measure change in a set area of the scalp, so they do not show how any one man’s hair will look.

What side effects does the prescribing information report?

In the Propecia hair-loss trials, Table 1 of the prescribing information lists decreased libido in 1.8% of men vs 1.3% on placebo, erectile dysfunction in 1.3% vs 0.7%, and ejaculation disorder in 1.2% vs 0.7%. It also says finasteride lowers PSA, a blood test used to screen for prostate cancer (Propecia prescribing information).

When should you talk to a doctor?

Talk to a licensed provider if you have sexual side effects, have a PSA test coming up, or have a partner who is or may be pregnant and has handled crushed or broken finasteride tablets, which the Propecia prescribing information warns against (Propecia prescribing information). Tell your provider about every medication you take.

How does the finasteride timeline compare with minoxidil and dutasteride?

Minoxidil timepoints are covered in what minoxidil trials report by timepoint. For studies that gave both drugs together, see finasteride and minoxidil together. For how the two drugs were compared one against the other, read minoxidil vs finasteride. In a 24-week trial of 917 men aged 20 to 50, the authors reported that dutasteride 0.5 mg significantly increased hair count compared with finasteride 1 mg (P = .003), and that the number and severity of adverse events were similar across groups (Gubelin Harcha et al., 2014). PrescribedRX does not offer dutasteride; more trial data are in dutasteride vs finasteride.

Where does Hair We Grow fit?

Hair We Grow is offered through PrescribedRX. Its product page lists it as finasteride plus minoxidil in one daily capsule. It is compounded. Compounded medications are prepared by licensed pharmacies and are not FDA-approved. None of the studies on this page tested Hair We Grow, so their results do not describe it.

• 3 month plan $220 · $73/mo · Billed every 3 months. Cancel anytime.
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A licensed provider decides whether it is appropriate for you, and your provider sets the dose. Other options are on the hair loss treatments page and the pricing page.

Frequently asked questions

Does finasteride regrow hair?

The Propecia prescribing information reports that an expert photo panel rated 48% of men on finasteride as having an increase in hair at 1 year and 66% at 2 years, versus 7% on placebo. At 5 years, 48% were rated increased, 42% unchanged and 10% as having lost hair.

How long does finasteride take to work?

The Propecia prescribing information says daily use for three months or more is generally necessary before benefit is observed. Men’s self-ratings showed a difference from placebo as early as 3 months, and hair counts were significantly higher than placebo at 6 and 12 months.

Do the results last after stopping?

According to the Propecia prescribing information, no. Men switched to placebo after 1 year lost the hair count increase by 24 months, and it says withdrawal leads to reversal of effect within 12 months.

Questions about finasteride? Talk to a licensed provider

Hair loss treatments offered through PrescribedRX are listed on the hair loss page. A licensed provider reviews your answers, and a prescription is issued only if they determine treatment is appropriate. You can check your eligibility first; availability varies by state.

Sources

1. DailyMed, National Library of Medicine. PROPECIA (finasteride) tablets prescribing information (updated Oct 2024). dailymed.nlm.nih.gov. Accessed Oct 2026.
2. Kaufman KD, et al. Finasteride in the treatment of men with androgenetic alopecia. Finasteride Male Pattern Hair Loss Study Group. J Am Acad Dermatol. 1998;39(4 Pt 1):578-589. PubMed. Accessed Oct 2026.
3. Finasteride Male Pattern Hair Loss Study Group. Long-term (5-year) multinational experience with finasteride 1 mg in the treatment of men with androgenetic alopecia. Eur J Dermatol. 2002;12(1):38-49. PubMed. Accessed Oct 2026.
4. Rossi A, et al. Finasteride, 1 mg daily administration on male androgenetic alopecia in different age groups: 10-year follow-up. Dermatol Ther. 2011;24(4):455-461. PubMed. Accessed Oct 2026.
5. Gubelin Harcha W, et al. A randomized, active- and placebo-controlled study of the efficacy and safety of different doses of dutasteride versus placebo and finasteride in the treatment of male subjects with androgenetic alopecia. J Am Acad Dermatol. 2014;70(3):489-498. PubMed. Accessed Oct 2026.

This article is for general information. It is not medical advice and it is not a recommendation for any particular treatment. Whether a treatment is appropriate for you is a decision for a licensed clinician who has reviewed your health history and current medications.