International non-proprietary name · Minoxidil

Minoxidil: the third item on this site to carry 'strong evidence'

Vehicle-controlled trials: two in women (381 over 48 weeks, 404 over 24) and two in men (352 over 16 weeks, 90 over 36). In all four, 5% beat vehicle on hair count. But 2% did not differ from vehicle on the users' own assessment, 10% was not better than 5%, and oral minoxidil did not beat topical.

Last checked Sep 21, 2026

Start here

What it is: A liquid or foam applied to the scalp. It was developed as a blood pressure drug, and hair thickening seen in the people who took it led to a topical version.
What it is used for: Androgenetic hair loss, male and female pattern. Applied to the scalp once or twice a day.
How it is said to work: It is said to widen blood vessels and lengthen the growing phase of the follicle. Exactly how it works has still not been fully settled.

There are no numbers and no citations in this box. What has been established, and how far, is below.

At a glance

Category: Over the counter — ask the pharmacist
How well established: Strong evidence
Concentration studied: 2–10%
Length of the studies: 16–48 weeks

“Concentration studied” and “Length of the studies” are taken straight from the research on this page. They are not a recommended dose, and the figure for each finding is written out in the text.

This is not how large the effect is but how well confirmed it is. It shows the highest grade among the findings on this page.

Whether and how to use it is decided with a doctor or pharmacist.

Korean classification Being checkedThe regulatory class has not yet been confirmed against a primary document. It will be filled in once it is.

One thing first. We could not confirm this drug's classification in Korea from primary sources. The 'category' label above reflects where the topical form sits in countries where it is approved; how it is handled domestically is outside what we verified.

Minoxidil was developed as a blood pressure drug. Hair thickening was noticed in the people taking it, and that side effect became its present use.

This is the third item on this site to carry 'strong evidence'. The first two were sunscreen and prescription retinoids.

The reason is the rule as written: two phase 3 trials against the same formulation with the drug removed, with 381 and 404 participants, over 48 and 24 weeks, with hair counted by people as the endpoint. The reason we held cysteamine down — individual trials of 20 to 40 people — does not apply here.

When this page first went up, it had only the two trials in women. That is why the title carried the qualifier 'in female pattern hair loss'. We have since verified two vehicle-controlled trials in male pattern hair loss and added them below, and dropped the qualifier. But the trials in men are smaller and shorter than the ones in women. We say so in the text rather than letting the badge stand alone.

And this site does not cover oral prescription medicines. That is why the most widely used option in hair loss is absent here; it is settled in consultation.

What is established

Strong evidenceConcentration studied 5%

Two vehicle-controlled phase 3 trials in female pattern hair loss pointed the same way

Start with the 2004 trial: a 48-week, double-blind, placebo-controlled, multicentre study in 381 women aged 18 to 49.

5% solution: 153
2% solution: 154
Placebo (the vehicle for the 5% solution): 74

Applied twice daily. The primary endpoints were change in non-vellus hair count at week 48 and patient and investigator assessments of hair growth and scalp coverage.

The 5% arm was superior to placebo on all three primary endpoints.

The 2016 trial used a different formulation: a 5% foam without propylene glycol, in a phase 3 randomised, double-blind, vehicle-controlled trial across 17 sites with 404 women. Once daily, 24 weeks.

10.9 more hairs/cm² than vehicle foam at week 12
9.1 more at week 24 (both P < .0001)
Scalp coverage improved by 0.69 points on subject self-assessment and 0.36 on expert panel review (both P < .0001)
Total unit area density also rose 658 and 644 µm/cm² more at weeks 12 and 24

Why we raised this to 'strong evidence'.

That badge is rare on this site. Cosmetic trials usually run 20 to 40 people over 4 to 12 weeks with the manufacturer paying, and do not meet the conditions.

This is different. Two separate trials, around 400 people each, 24 and 48 weeks, controlled against the same formulation with the drug removed, with hair counted by people. The directions agree. The reason we graded cysteamine down — trials too small — does not apply.

That is where the trials in women end. The vehicle-controlled trials in male pattern hair loss are written up as the next item below. We did not fold them into one entry, because the numbers and the durations are not alike.

Randomised controlled trial in people · 381 participants · 48 weeks · Compared with vehicle (same formula minus the active) · Funding not declared · Endpoint clinical events (cancers, lesion counts) PMID 15034503
Randomised controlled trial in people · 404 participants · 24 weeks · Compared with vehicle (same formula minus the active) · Funding not declared · Endpoint clinical events (cancers, lesion counts) PMID 27391639

Strong evidenceConcentration studied 5%

In male pattern hair loss, two vehicle-controlled trials pointed the same way

The 2007 trial first. Published in JAAD: multicentre, randomised, double-blind, placebo-controlled, with 352 men aged 18 to 49 using a 5% foam with no propylene glycol for 16 weeks.

At week 16, against baseline:

hair counts rose significantly over placebo (P < 0.0001)
so did the users' own assessment of their hair loss (P < 0.0001)

143 of them then continued into an open-label phase for 52 weeks of safety data.

The 2021 trial ran 36 weeks at Zagazig University in Egypt: randomised, double-blind, placebo-controlled, 90 men with male pattern hair loss split into 5% solution, 10% solution and placebo.

Change from baseline in mean hair count at week 36. The abstract does not give a unit, so we carry the numbers alone.

vertex — 5% 0.47, 10% 0.05, placebo 0.01
frontal — 5% 0.59, 10% 0.45, placebo −0.03

In both trials, 5% beat placebo. So this entry carries 'strong evidence' too.

It is thinner than the female side. Above, the trials were 381 over 48 weeks and 404 over 24. Here they are 352 over 16 weeks and 90 over 36. The larger one is short; the longer one has 90 people.

Same badge, different thickness underneath it. There is no room beside a badge to say that, so we say it here.

Randomised controlled trial in people · 352 participants · 16 weeks · Compared with vehicle (same formula minus the active) · Funding not declared · Endpoint clinical events (cancers, lesion counts) PMID 17761356
Randomised controlled trial in people · 90 participants · 36 weeks · Compared with vehicle (same formula minus the active) · Funding not declared · Endpoint clinical events (cancers, lesion counts) PMID 31403367

Not establishedConcentration studied 10%

10% was not better than 5% — only more irritating

Set the three arms of that same 2021 trial side by side and raising the concentration did not improve the result.

At week 36 the change in vertex hair count was 0.47 for 5%, 0.05 for 10%, 0.01 for placebo. The 10% arm came in below 5%, and close to placebo. On the frontal scalp, 10% (0.45) fell a little short of 5% (0.59).

Pull tests turning negative: 37% on 5%, 37.5% on 10% — alike — against 0% on placebo.

And irritation was marked on 10%. The authors write that shedding and irritation, set against high expectations, left the people on 10% worse off psychologically.

Why this sits under 'not established'. It comes from a single 90-person trial. One trial cannot settle that 10% is worse than 5%.

But the other direction is in the same position. 'Stronger is better' is not supported by this trial either. We hold both directions to the same standard.

Worth noting that the approved concentrations are 2% and 5%, and this result does not sit against that.

Randomised controlled trial in people · 90 participants · 36 weeks · Compared with another active ingredient · Funding not declared · Endpoint clinical events (cancers, lesion counts) PMID 31403367

Not establishedConcentration studied 2%

At 2%, the users themselves could not tell it from placebo

These are the results for the 2% arm (154 people) of the same 2004 trial.

2% did beat placebo — on hair count and on the investigator's assessment of hair growth and scalp coverage.

But on the participants' own assessment of hair growth, it did not differ significantly from placebo.

And 5% was statistically superior to 2% on exactly that measure.

What this tells you. On the scalps of the people using 2%, hair really did increase. The people using it could not see the change.

This site separates 'what measured differently' from 'what looks different in a mirror'. This trial shows the seam between the two exactly. It is a number worth seeing when choosing a strength.

Randomised controlled trial in people · 381 participants · 48 weeks · Compared with vehicle (same formula minus the active) · Funding not declared · Endpoint self-reported improvement PMID 15034503

Moderate evidenceConcentration studied — Not established

Oral minoxidil did not beat topical

This is a 2024 Brazilian trial, published in JAMA Dermatology.

Men aged 18 to 55 with male pattern hair loss received either oral minoxidil 5 mg once daily or topical 5% minoxidil twice daily for 24 weeks. Double-blind, placebo-controlled and randomised; 90 enrolled and 68 completed (33 oral, 35 topical).

Change from baseline to week 24 in the frontal area, between groups:

Terminal hair density 3.1 hairs/cm² (95% CI −18.2 to 21.5, P = .27)

The authors' conclusion, in their words: oral minoxidil 5 mg once per day for 24 weeks did not demonstrate superiority over topical minoxidil 5% twice per day.

Look at the width of that interval — from −18.2 to 21.5. This trial does not say the two are the same. It says it had no power to tell which was better. With 68 completers, that is what happens.

And this site does not cover oral minoxidil. Dosing, and checks on blood pressure and the heart, are settled in consultation. This item is here to record that 'the oral one is stronger' is not supported by this trial.

Randomised controlled trial in people · 90 participants · 24 weeks · Compared with another active ingredient · Funding not declared · Endpoint clinical events (cancers, lesion counts) PMID 38598226

Known risks

We could not confirm the domestic classification from primary sources. The 'category' label above is where the topical form sits where it is approved.
Shedding can increase in the first few weeks. It is explained as resting follicles entering a new cycle together, and it usually passes. Not knowing this is a common reason people stop.
Scalp irritation and itching are common. The 2004 solution contained propylene glycol; the 2016 foam was formulated without it.
Fine hair can increase on the face. The 2016 trial reported this; it happens where the product runs.
It holds only while you apply it. Stop and what was gained goes back over some months.
If you have heart disease or take blood pressure medication, check in consultation first. This was a blood pressure drug to begin with.
Use in pregnancy and breastfeeding is settled in consultation.

What is not established

The trials in men are smaller and shorter than the ones in women. 352 over 16 weeks and 90 over 36; nothing in men runs as long as the 48-week trial in women.
Only one trial compared 10% with 5%. It had 90 participants, and its result did not favour 10%.
The 2021 abstract does not state the unit for its hair-count change. So we carry the numbers over without attaching one.
How long you should keep using it has no answer here. The longest look was 48 weeks.
We could not include a trial measuring how quickly it reverses after stopping.
The comparison with oral minoxidil rests on one trial with 68 completers, and the interval was too wide to separate them.
Data on combining it with other treatments are not on this page.

Whether and how to use it is decided with a doctor or pharmacist.

What this article relies on

PubMed — 미국 국립의학도서관 문헌 데이터베이스National Library of Medicine · Checked on 2026-09-16