Before: what the trials started with
The registration trials enrolled 1,553 men aged 18 to 41 with male pattern hair loss at the vertex and randomized them to finasteride 1 mg a day or placebo. The “before” was a hair count inside a 1-inch circle (5.1 cm2) of balding vertex scalp, which averaged 876 hairs, plus patient and investigator assessments and standardized photographs reviewed by an expert panel. Finasteride works by inhibiting type II 5-alpha-reductase, which lowers scalp and serum DHT, the androgen that miniaturizes the follicle. Everything that follows is measured against that baseline.
After one year and two years
At one year, the finasteride group had 107 more hairs in the circle than the placebo group; at two years, with 1,215 men continuing in blinded extensions, 138 more. The placebo group lost hair progressively across the same period, so the gap is finasteride adding hair on one side and untreated loss on the other. Every evaluation method agreed: hair counts, patients’ own assessment (slowed loss, more growth, better appearance), investigators’ assessment, and the blinded photo panel, all at P < .001 versus placebo. The authors described adverse effects as minimal.
After five years
The same cohort continued in up to four further one-year placebo-controlled extensions. Over five years, finasteride led to durable improvement in scalp hair on every endpoint while placebo led to progressive loss, and no new safety concerns appeared with long-term use. This is the study to read when someone asks whether the effect wears off: in the trial, it did not, and the untreated course kept going the other way.
Hair weight: the number the photos are trying to show
A smaller study of 66 men weighed the hair clipped from a marked area as well as counting it. At 48 and 96 weeks the net gain over placebo was 9.2% and 15.4% in hair count, and 25.6% and 35.8% in hair weight. Extended to 192 weeks, finasteride had raised hair weight 21.6% from baseline while placebo had lost 24.5%, a net difference of 46.0%; hair count was up 7.2% against a 13.0% placebo loss, a net 20.3%. Weight rising faster than count means the treated hairs also grew longer and thicker, which is what a before-and-after photo is registering when the scalp looks more covered than the count alone would predict. The sample shrank as the study ran on, which the authors list as a limitation.
The front of the scalp, and men up to 60
The vertex trials did not answer the question most men ask, which is about the hairline. A separate one-year double-blind, placebo-controlled trial in men with frontal, anterior and mid-scalp thinning counted hairs in a 1 cm2 frontal area and found a significant increase on finasteride, with patient, investigator and photographic assessments improved and the effect maintained or increased through a one-year open extension. A later photographic analysis of men aged 18 to 60 found growth versus placebo in every scalp region at 24 months; loss slowed in all areas in the younger men, but only at the vertex and anterior/mid scalp in the older men, and the finasteride group reported slightly more drug-related sexual adverse experiences at every age. The finasteride and erectile dysfunction guide covers that side of the ledger.
Women: the trial that found nothing
In a one-year randomized, placebo-controlled trial, 137 postmenopausal women aged 41 to 60 with androgenetic alopecia took finasteride 1 mg or placebo. There was no difference in the change in hair count, both groups lost hair in the frontal and parietal scalp, and none of the patient, investigator, photographic or biopsy assessments showed any benefit. Finasteride 1 mg is FDA-approved for men; the FDA-approved hair loss treatments for women guide covers what is.
The timeline, and stopping
The trials reported at one year, then two, then five, and the gain over placebo grew between year one and year two. Read your own before-and-after on that clock: months in, the honest comparison is against where you would be untreated, not against a fuller head. The placebo arms show that untreated course, progressive loss at every time point, so the benefit depends on continuing. Finasteride is maintenance treatment. The finasteride for hair loss guide covers how it works and what to expect month to month, and the minoxidil before and after guide gives the same treatment to the other half of the plan.
How to get finasteride online
Finasteride 1 mg is a prescription medicine. At PepScribe the online visit is free. A US-licensed clinician reviews your history, and if prescribed, you receive a daily capsule combining finasteride, minoxidil and biotin, compounded in the USA by a licensed 503A pharmacy, from $29/mo with the medication, clinician care and shipping included. The combined capsule is not FDA-approved as a combination product. PepScribe makes no regrowth guarantees; the clinician sets expectations from the evidence above. The hair loss treatment page describes what PepScribe offers.
Frequently asked questions
What does finasteride before and after look like in the trials?
In 1,553 men aged 18 to 41, a 1-inch circle of balding vertex scalp held 876 hairs at baseline. After one year of finasteride 1 mg, the count was 107 hairs higher than placebo; after two years, 138 higher, while the placebo group kept losing hair. Patients, investigators and a blinded photo panel all rated the finasteride group as improved.
How long does finasteride take to show results?
The trials reported their first endpoints at one year and the gain grew by year two. Judge it in years, not weeks. The five-year extension found the improvement durable while untreated men kept losing hair.
Does finasteride thicken hair or only add hairs?
Both, and thickness more. At 96 weeks the net gain over placebo was 15.4% in hair count and 35.8% in hair weight; at 192 weeks, 20.3% in count and 46.0% in weight. Weight rising faster than count means the hairs also grew longer and thicker.
Does finasteride work on the front of the scalp?
In a one-year placebo-controlled trial of men with frontal, anterior and mid-scalp thinning, finasteride 1 mg significantly increased hair count in a 1 cm2 frontal area, with improvements maintained or increased in the second year.
Does finasteride work for women?
Not in the trial that tested it: 137 postmenopausal women aged 41 to 60 took finasteride 1 mg or placebo for a year and there was no difference in hair count or in any assessment. Finasteride is FDA-approved for men.
What happens if I stop finasteride?
The placebo arms show the untreated course: progressive loss at one, two and five years. The benefit depends on continuing. Finasteride is maintenance treatment.
