Oral minoxidil for hair loss: what the trials show, and how it compares with the scalp forms

Minoxidil is best known as a foam or a liquid applied to the scalp twice a day. The same medicine also comes as a tablet, and one tablet a day sounds easier and, to many people, stronger. This page sets out what the research we reviewed says about that: what the tablet was compared with, what it did to hair counts, which side effects were recorded and what has not been measured.

It is written for adult men with male pattern hair loss, the gradual thinning at the hairline or the crown. If your hair is falling out suddenly or in patches, or your scalp is sore, the type of hair loss comes before any product.

What oral minoxidil is

ConditionalMedicine · Off-label for hair loss in the US and UK

Oral minoxidil is minoxidil taken by mouth. In the United States and the United Kingdom the tablets are authorised for high blood pressure, not for hair loss. Taking them for hair is an off-label use, meaning a use the label does not cover, and that makes it a prescriber's decision. The scalp forms are in a different position: in the US the men's 5% solution and foam are sold over the counter, and in the UK the men's foam is on general sale. ^{[1, 2, 3, 4, 5]}

Studies usually call it "low-dose oral minoxidil". Low is a loose word here. The thesis of the dose trial uses it for 0.25 mg to 5 mg a day, while the large study of clinic records that carries the same name recorded doses from 0.03 mg to 15 mg. None of the tablet labels we checked gives a dose for hair loss. ^{[6, 7, 1, 2]}

In our ranking, minoxidil shares the top tier with finasteride. That position rests on the solution and the foam, and the tablet does not inherit it. In our library the tablet form carries the label "Conditional": a route to compare when applying something to the scalp is not accepted, not sustainable or not suitable. The minoxidil profile sets the three forms side by side.

Tablet against solution: the head-to-head trial

Whether the tablet beats the liquid can be checked against one trial that compared the two routes directly in men. It was run at a single centre in Brazil and published in 2024. ^[8]

The main result

The main measure was the density of terminal hairs, the thicker ones. After 24 weeks minoxidil by mouth had not proved better than the solution at either site. At the front of the scalp the oral group was ahead by 3.1 hairs per square centimetre, with a plausible range from 18.2 fewer to 21.5 more. At the crown the oral group was ahead by 23.4, with a range from 0.3 fewer to 43.0 more. ^[8] The page on minoxidil and a receding hairline looks at what the front-of-scalp result does and does not say about a hairline.

What the photographs showed

Trials also report secondary results, the ones that sit beside the main question. On photographs of the crown, the share of men rated as improved was 24 percentage points higher in the oral group, with a range from 0 to 48. ^[8]

This secondary result favours the oral group. It is a rating of pictures, not a count of hairs, and a secondary result cannot overrule the main one. It also says nothing about speed. Hair was assessed at 24 weeks, and the trial was not designed to time how soon a change appears.

Who dropped out, and why it matters

Twenty-two of the 90 men did not finish. Most of them could not attend because of the pandemic. Four stopped because of side effects: one in the oral group and three in the solution group. The hair counts come from the 68 who completed, so about a quarter of the men who started are missing from the main result. The report describes its analysis as covering everyone who was randomised, yet the men with missing counts were left out, and we did not find an analysis testing whether the missing men could change the result. ^[8]

The trial's registry entry and its published report also describe the hair measurement differently: which areas were measured, and how thick a hair had to be to count as terminal. We could not retrieve the documents that would explain the difference. It is an unexplained difference, not proof that the measure was changed after the results were seen. ^{[9, 8]}

2.5 mg against 5 mg: the dose trial

A second trial, also at a single centre, asked whether a higher dose by mouth does more. One hundred men aged 25 to 55 were randomly given 2.5 mg or 5 mg once a day for 24 weeks, 50 in each group, and neither they nor the researchers knew who was taking which. Ninety-two completed. Men with heart, blood-vessel or kidney conditions were excluded. ^[6]

The main measure this time was all hairs except the finest. The trial reports a difference of 0.9 hairs per square centimetre between the two doses, with a range from 2.6 fewer to 4.5 more. Counting every hair, the difference was 3.6, with a range from 2.6 fewer to 9.7 more. Neither result shows an advantage for the higher dose, and neither proves that the two doses do the same. ^[6]

We know this trial from its thesis and its supplementary table. The journal article, published online in September 2025, was not available to us, and a thesis is not the final peer-reviewed version. Some details differ between the thesis summary and its own tables, and between the thesis and the registry entry, which planned 90 men where the thesis reports 100. The thesis declares no funding and no conflicts of interest, and the registry lists support from the institution. ^[6]

Unwanted hair growth was reported by most men at either dose. Swollen lower legs were recorded in two men and dizziness in two, all on the higher dose. In this trial the higher dose did not show more hair, and the lower one still came with side effects.

The doses that appear in the research

"Low dose" is not one amount. These are amounts described in the trials, in one clinic's records and in one case report behind this page.

The rows come from the two trials in men, one trial in women, a review of clinic records and a single case. ^{[8, 6, 10, 11, 12]}

Side effects recorded with the tablets

A tablet acts on the whole body, so its side effects are not the scalp irritation of a liquid. Three kinds of source describe them, and they answer different questions: a trial with a comparison group, a large set of clinic records without one, and warnings about rare serious events. Our page on minoxidil side effects covers the scalp forms as well.

In the head-to-head trial

The 90-man trial shows a trade. Men on minoxidil by mouth had more hair growing where it was not wanted and more headaches. Men on the solution had more scalp eczema, and more of them stopped because of side effects. Blood pressure and heart rate did not differ significantly between the groups, in men who had been selected for having no heart or kidney disease. ^[8]

Early shedding was counted too. A temporary increase in the first two months was recorded in 4 of the 45 men in the oral group and 7 of the 45 on the solution. As with the scalp forms, early shedding is not a test of whether the treatment will work. ^[8]

In the records of 1,404 people

A larger picture comes from a study that pooled the records of 1,404 people taking low-dose tablets for hair loss at several clinics, followed for 7.9 months on average. It had no comparison group. Because 1,065 of those people were treated at more than one dose, the study analysed 2,469 dose records, and its percentages are worked out on those records. ^[7]

The paper counts 43 patients who stopped because of a side effect: 14 for unwanted hair growth and 29 for effects on the rest of the body. No life-threatening event was seen. The authors declared no funding and no conflicts of interest. A study of this kind cannot show that the risk of a rare event is zero. ^[7]

Serious events: label warnings and one case report

For serious events there is no reliable figure to give. The US tablet label, written for blood-pressure treatment, carries a boxed warning about fluid collecting around the heart, which can go on to press on it, and about worsening angina. Those warnings come from blood-pressure use. Their frequencies cannot be carried over to the amounts used for hair, in either direction. ^[1]

One published case describes fluid around the heart and lungs, with widespread swelling, in a 40-year-old woman three weeks after she started 0.25 mg a day. She had a fibrosing alopecia, a different condition from pattern hair loss, and was taking several other medicines. It cleared after she stopped the tablets and was treated in hospital. ^[12]

What the labels and the consensus statement say

Neither tablet label we checked covers hair loss. Two kinds of document fill that gap: the tablet labels written for blood pressure, and a statement in which hair specialists agreed how to start the tablets off-label. ^{[1, 2, 13]}

The consensus statement is written for prescribers. We do not repeat its guidance on starting and adjusting doses, because it is expert opinion for a clinician to apply to one patient, not an instruction for readers. For the scalp forms the labels do give instructions, and how to use minoxidil goes through them.

Who the trials left out, and who needs advice first

The numbers on this page come from selected men. That limits who they describe.

Tablets, solution and foam compared

The three forms deliver the same medicine, but their evidence, their instructions and their risks are not interchangeable. The table puts them next to each other on the points a decision turns on.

For the choice between the two scalp forms, see minoxidil foam and liquid compared. What the tablet offers against either of them comes down to a short list.

Switching from a scalp product, or using both

The head-to-head trial tested the two routes as alternatives. It says nothing about taking a tablet on top of a scalp product, and no study we reviewed establishes a schedule for moving from one to the other. The pairings below have been described, not proven. ^{[8, 11, 17]}

What the tablets cost

We recorded one price, at a UK online pharmacy on 29 September 2026: £74.99 for a pack of 120 tablets of 2.5 mg. Worked out at the amounts the trials used, that is £18.75 for 30 days at 2.5 mg a day and £37.50 at 5 mg a day, costed as two 2.5 mg tablets. We did not record a US price for the tablets. The scalp products are shown beside them, from the same price check.

Over a year of use the tablets come to about £228 at 2.5 mg a day and £456 at 5 mg a day, before the consultation. The doses are the ones the trials tested, used here only to make the sums comparable. Price says nothing about which form works better, and the higher figure pays for a dose that was not shown to grow more hair than the lower one. The minoxidil profile has the full cost comparison.

What is not known

Some of these gaps are gaps in what we could read, not in what exists. The final article of the dose trial and at least one study of tablets used together with a scalp product were identified but not available to us. Our methodology explains why we stop where the sources stop.

Where to go next

If you are weighing a tablet because twice a day on the scalp is hard to keep up, the practical comparison is with the form you would otherwise use, and the conversation is with a prescriber. If you have not yet tried a scalp form, the main guide to male pattern hair loss starts with the two core options: minoxidil on the scalp and finasteride tablets. For the other core option, see minoxidil and finasteride compared.