Minoxidil

Minoxidil is one of the two mainstays of medical treatment for androgenetic alopecia, alongside finasteride. It exists in two forms that share a name and do not behave alike: a solution or foam applied to the scalp, and tablets taken by mouth at a low dose.

Topical minoxidil

Applied minoxidil is the established form: health authorities approved it in 1988 for male androgenetic alopecia, under the brand name Rogaine. The concentration ranges from 2% to 5%, the higher one generally being recommended for men. It is applied to a dry scalp once or twice a day, 1 ml per application (marked on the dropper), and the hair should not be wetted for about four hours afterwards. There is no need to shampoo before each use.

Its drawbacks are mostly practical. It has to be applied every day, for as long as the benefit is wanted, and regularity is what most often fails. Local irritation, itching or flaking can occur, and unwanted facial hair is possible when the product runs or is transferred.

Low-dose oral minoxidil

Minoxidil tablets were developed to treat high blood pressure. Their use at a low dose against hair loss is off-label: it rests on a growing body of clinical studies, not on a marketing authorisation for this indication. It is a prescription treatment, decided patient by patient by a physician, who sets the dose and first checks that nothing argues against it, heart or kidney disease, low blood pressure, pregnancy or breast-feeding in particular.

The side effects to know about are increased hair growth on the face or body, the most frequent, and more rarely ankle swelling, a faster heartbeat, dizziness or headache. They depend on the dose and usually settle when it is lowered or the treatment stopped. Chest pain, breathlessness or marked swelling mean stopping the treatment and seeking medical advice.

How does minoxidil work?

Its effect on hair was first noticed as a side effect of the blood-pressure medicine. Minoxidil opens potassium channels and prolongs the growth phase of the hair cycle, which thickens miniaturised hairs. How exactly it does so is still not fully understood, and better blood flow alone does not explain it. It does not act on the hormonal cause of androgenetic alopecia: that is the role of finasteride, which is why the two are often combined.

What can I expect, and when?

Increased shedding is common during the first weeks: hairs at the end of their cycle fall to make way for new ones. It is temporary and is not a reason to stop. It usually takes three to four months of regular use before an improvement shows, and up to a year to judge the treatment fairly. The benefit lasts only as long as the treatment does: if it is stopped, the hair that has regrown generally falls out within about three months.

What if I forget a dose?

Take or apply it as soon as possible, and only one dose if the time of the next one is close. Do not double up.

And around a hair transplant?

Applied minoxidil, whether solution, spray or foam, is stopped three days before the procedure. It is not resumed afterwards until Dr Seffen allows it: applied to a grafted area, it irritates a scalp that has already been through enough and shifts grafts that are not yet held by anything.

Oral minoxidil, in tablet form, follows different rules: in the clinic's protocol it is resumed from the second day after the procedure, at a low dose. The two forms share a name and do not behave alike; the post-operative sheet you are given says so.