What the number on a minoxidil carton means

The number on the front of a minoxidil carton is a concentration: how much of the active ingredient is present in the formulation. It is written as "Minoxidil 5% w/v" on a solution, meaning weight in volume, and as "Minoxidil 5% w/w (without propellant)" on a foam, meaning weight in weight, because a foam is weighed rather than measured out.

It is not a dose, it is not a strength rating in the sense of "better", and it is not a recommendation aimed at anyone. This page explains what it describes and what the labels claim about the difference. It does not tell you which one to buy, and it does not carry any directions for use — that is what the carton and a clinician are for, and repeating a carton's instructions here would not make them ours to give.

Concentration is not dose

These are different ideas and conflating them is the root of most confused conversations about this drug.

A concentration describes the formulation in the bottle: what proportion of it is the active ingredient. A dose describes what a person actually receives: how much formulation, applied to how much skin, how often, over what period. Two of those variables are on the carton's directions and one of them is you.

That is why a percentage on a box tells you much less than it appears to. It is a property of the product, and the product is only one term in the equation.

Why two strengths exist at all

Because they were approved separately and at different times, each with its own trial evidence, and the labels reflect that history.

The lower-strength men's label carries a trial paragraph of its own: in studies of "mostly white men aged 18-49 years with moderate degrees of hair loss", "26% of men reported moderate to dense hair regrowth" after four months, against "11% of men reporting hair regrowth after using the placebo". Minimal regrowth was 33% against 31%.

The higher-strength men's label makes a comparative claim, and a carefully limited one: minoxidil topical solution 5% for men "provided more hair regrowth than minoxidil topical solution 2%" in clinical studies with the same kind of population. What it does not do is put a number on "more". No approved label read for this site quantifies the gap, so neither will we.

What the higher-strength label does not claim

• It does not claim to work faster. Its own timing sentences are the same ones the lower strength uses: a shed of up to two weeks at the start, results possibly at two months under the label's directions, at least four months for some men, and a four-month point at which the label tells users without regrowth to stop and ask a doctor.
• It does not claim to work for people the lower strength failed.
• It does not claim to work outside the area either product is approved for. Both say the product is "not intended for frontal baldness or receding hairline" and describe use on the top of the scalp, "vertex only".
• It does not claim a different safety profile. The "stop use and ask a doctor" lists on these panels are the same.

The strengths are not the same product for everyone

Men's and women's minoxidil products are labelled separately, tested in different populations, and sold in different strengths in different formats. A men's carton says plainly "do not use if you are a woman" — a statement about which product was studied in whom rather than a claim about anyone's biology. That is one reason "which percentage is best" has no general answer: the question already assumes a person.

Add the label's other exclusions — under 18, an irritated or painful scalp, other medicines on the scalp, sudden or patchy hair loss, hair loss with no known cause or no family history, and a separate instruction to ask a doctor first if you have heart disease — and it becomes clear that the number on the front is one of the less decisive things on the box.

Why there is no recommendation here

Because it would be a dose recommendation in disguise, and this site does not make those. Choosing a concentration is choosing how much active ingredient meets a scalp, which is a clinical decision about one person's skin, one person's pattern of loss and one person's tolerance for the things on the stop-use list. A page that does not know any of those cannot make it.

What this page can do is remove the mystique. The number is a concentration. The higher one has a comparative claim on its label with no figure attached. The rest of both labels — the exclusions, the timings, the warnings, the fact that stopping costs the regrowth — is identical, and it is where the useful information lives. The whole of it is on the main page.

Reading a carton in the shop

Four lines are worth finding before anything else, and they are all on the panel rather than the front:

1. Active ingredient. This tells you whether it is a medicine at all. Products without this line are not minoxidil, whatever the box says about growth.
2. Purpose. "Hair regrowth treatment for men" or the women's equivalent — this is the approved claim, and it is narrower than most marketing.
3. Inactive ingredients. Where the carrier lives, and therefore where irritation usually comes from. That comparison is here.
4. Stop use and ask a doctor if. Six lines that are the same across brands and strengths, and the only part of the carton that tells you when to involve somebody else.

If the two cartons in your hands differ only in the first line, they are the same medicine at different concentrations. If they differ in the third, that is the difference worth thinking about.