Minoxidil
Minoxidil was a blood pressure drug before anyone noticed what it did to hair. Applied to the scalp, it lengthens the growth phase of the hair cycle and increases the size of miniaturising follicles, so existing hairs grow for longer and thicker than they otherwise would.
It does not block DHT and it does not address why the loss is happening. It works on the follicles rather than the cause, which is why it pairs so naturally with finasteride and why using both is standard for anyone with active loss.
It is available without a prescription almost everywhere, in 5% and 2% strengths, as a liquid or a foam.
On this page
What to expect from it
Visible thickening rather than new coverage. Areas that are thinning respond best, the crown responds better than the hairline, and skin that has been completely bare for years responds least.
The effect is modest and it is real. In the trials, most users either maintained or improved over a year, with the improvement concentrated in the vertex. It will not rebuild a hairline and it is not competing with surgery.
Where it earns its place is as the low-cost, low-risk baseline. Anyone with early thinning who does not want a systemic drug should be using it, and anyone already on finasteride generally does better with both.
Foam, liquid and oral
Liquid minoxidil contains propylene glycol, which irritates a good number of scalps and can leave hair looking greasy. Foam avoids the propylene glycol, dries faster and is more pleasant to use. Both work. Adherence is what differs, and the version you will actually apply twice a day is the better one.
Application matters more than people think. It goes on the scalp, not the hair, twice daily, on a dry scalp, and it needs a few hours before washing. Missing doses is the commonest reason it appears not to work.
Oral minoxidil at low dose is increasingly prescribed off-label, and the results reported are better than topical for many people. It is a systemic drug with real cardiovascular considerations, it commonly causes hair growth elsewhere on the body, and it needs a prescriber who will monitor you. It is not a self-service option.
When you start
Attach it to something you already do twice a day, like brushing your teeth, and keep it in the same place. This is a treatment that fails on adherence far more often than on biology.
Applying it properly
Part the hair in a few lines across the thinning area, put the product on the skin along each part and spread it with your fingertips. Product on the hair shafts is wasted and makes the hair look flat.
Use the amount on the packaging. Doubling up does not double the effect, and it makes irritation and runs onto the forehead more likely. A missed dose is skipped, not made up.
Let it dry before lying down or putting on a hat, and wash your hands straight afterwards. Give it four to six months before judging it, on photographs rather than the mirror.
Oral minoxidil
For hair, oral minoxidil is prescribed at doses well below those once used for blood pressure. It is off-label, meaning the drug is licensed but not for this use, and the prescriber should explain what that means.
People choose it because a tablet is easier than a twice-daily routine, because the topical irritates them, or because the topical has not done enough.
The common side effect is extra hair elsewhere, on the face, forehead, arms and back. Others include ankle or facial swelling from fluid retention, palpitations, headaches and light-headedness on standing. Serious cardiac effects are uncommon at these doses, and they are why the prescriber should ask about your heart and blood pressure first.
It is a poor fit for anyone with significant heart disease or low blood pressure, and it interacts with other blood pressure drugs. Report swelling, chest pain, breathlessness or a racing heart promptly rather than waiting for a review.
The shedding phase
Two to eight weeks in, many people shed noticeably. It happens because minoxidil pushes follicles from their resting phase into a new growth phase, and the old hair has to come out for the new one to come through.
It looks exactly like the treatment making things worse. It is not, it settles within a couple of months, and it is a reasonable sign the drug is doing something.
Staying with it through the shed is what lets the new growth come through.
Side effects and stopping
Topically, most problems are local: itching, flaking, dryness or irritation, usually from propylene glycol in the liquid. Switching to foam solves most of it.
Unwanted hair growth on the face can happen, generally from the product transferring rather than systemically, and washing your hands after applying it largely prevents it. Rarely, people get dizziness or a racing heart, which is worth reporting.
Stopping returns you to baseline over three to six months, usually with a noticeable shed on the way. Everything it was holding is lost, so, as with finasteride, it works best as a long-term routine.
If your scalp reacts
Switch from the liquid to the foam before giving up on it entirely. Most irritation comes from propylene glycol rather than the minoxidil itself, and the foam leaves it out.
Around a transplant
Most surgeons ask you to stop topical minoxidil for a short period before the operation and restart once the scalp has healed, often one to four weeks afterwards, because it can irritate healing skin. Some like patients established on it beforehand, on the view that it may help native hair ride out shock loss. That is reasonable rather than settled.
If you take oral minoxidil, ask specifically whether to pause it, since it affects heart rate and blood pressure. Follow the clinic's written protocol over any general rule, including this page. The wider picture is on keeping a transplant.
Who should be careful, and pets
Topical minoxidil is not for pregnancy, breastfeeding or under-18s. Anyone with a heart or blood pressure condition should check with a doctor first, even for the topical. Do not use it on sunburnt, broken or inflamed skin.
Women can use it, and in many countries the women's products are the 2% liquid twice daily or the 5% foam once daily. Female pattern loss has its own questions, covered on women and hair restoration.
Cats are the risk people do not know about. They are extremely sensitive to minoxidil, and small amounts licked off a pillowcase, a hand or an owner's head can cause serious, sometimes fatal, poisoning. Dogs are at risk too, mostly from chewed bottles and spills. Keep it shut away, let it dry before contact, and do not let a cat sleep on your pillow. If a pet may have been exposed, call a vet straight away rather than waiting for symptoms. Keep it out of children's reach for the same reason.
If you live with a cat
Apply it at times when the cat is shut out of the bedroom, and change your pillowcase often. Treat the bottle like a medicine, because to a cat it is a poison.
Frequently asked questions
Foam or liquid?
Whichever you will actually use twice a day. Foam avoids the ingredient that irritates most scalps. See foam, liquid and oral.
Why is my hair falling out more since I started?
A shedding phase at two to eight weeks, as resting follicles restart. It settles. See the shedding phase.
Is oral minoxidil better?
Often more effective, and it is a systemic prescription drug with real considerations and body hair growth as a common effect. Not a self-service option. See oral minoxidil.
Can I use it with finasteride?
Yes, and it is the standard combination. They work by different mechanisms.
What if I stop?
You return to baseline over three to six months. See side effects and stopping.
Do I stop it before a hair transplant?
Usually for a short spell, restarting once the scalp has healed, on your surgeon's timetable. See around a transplant.
Is minoxidil dangerous for pets?
Yes, especially cats, which can be seriously poisoned by small amounts. See who should be careful, and pets.
Can women use minoxidil?
Yes, usually at the strengths marketed for women, and not in pregnancy or while breastfeeding. See who should be careful.