Minoxidil, a hair growth stimulating drug


Introduction to Minoxidil

Minoxidil is one of the drugs recommended and prescribed by trichologists and dermatologists for the treatment of androgenetic alopecia (or common baldness). It is the only drug, along with Finasteride, approved by the FDA (Food and Drugs Administration) in the United States against hair loss.

It is a topical therapy, i.e. applied directly to the scalp, and is available on the market in concentrations of 2% and 5%. It can reduce hair loss and, in some cases, encourage at least temporary regrowth.

General information

Minoxidil is available on the market under the following names:

    • Amexidil;
    • Minoxidil;
    • Regaine;
    • Aloxidil;
    • Minoximen;
    • Tricoxidil.

All these versions have a 2% or 5% solution, in combination with other products such as water, glycols and alcohols.

The 5% concentration is more effective. This is demonstrated by a study conducted in 1984 and published in the American Academy of Dermatology Journal, in which 393 people suffering from common baldness took Minoxidil at different concentrations over a period of 48 weeks, as follows:

    • 157 were prescribed Minoxidil 5% with two applications per day
    • 158 were prescribed Minoxidil 2% with two applications per day
    • The last group of 78 people took a placebo drug twice a day instead

At the end of 48 weeks, those using Minoxidil 5% experienced 45% more and faster hair regrowth than those taking Minoxidil 2%. At the same time, however, the first group complained of scalp irritation and itching.

Consequently, experts generally prescribe Minoxidil 2% in cases where hair loss is in its early stages, while Minoxidil 5% is recommended in more severe cases.

The history of Minoxidil

The American pharmaceutical company Upjohn Company was responsible for the birth of the active ingredient Minoxidil in the late 1970s. Initially, the drug was used against hypertension, thanks to its dilating capacity, which allowed a reduction in blood pressure. It was taken orally.

However, side effects included hypertrichosis and hair regrowth. For this reason, Minoxidil was considered for use against baldness.

To avoid side effects in individuals taking the drug without complaining of hypertension, it was decided to use it topically, applying it directly to the affected area.

Over the years, hypertension began to be treated with more effective drugs, and Minoxidil continued to be used for its beneficial effects on hair.

Minoxidil can only be purchased in pharmacies on prescription in its commercial forms. In addition, many pharmacies now offer effective galenic preparations and, in some cases, these are supplemented with additional active ingredients that make the preparation even more effective. For example, progesterone, cyproterone acetate, spironolactone, etc. are used.

How does Minoxidil work?

Minoxidil is a chemical compound designated by the formula C9H15N5O. It acts on hair loss by modifying the life cycles of the hair follicle. Specifically, it prolongs the anagen phase of the life cycle, i.e. the growth phase of the hair, and reduces the catagen and telogen phases as far as possible.

The drug leads to an increase in the production of beta-catenin, a specific protein, in the dermal papilla of the follicle and this synchronises the life cycle of all the follicles. As a result, the hair becomes longer and develops a larger diameter.

As already stated, Minoxidil has very good vasodilator abilities. This characteristic is not sufficient to promote hair growth, otherwise any drug that dilates blood vessels would bring the same benefits to the scalp.

Manner of use

Minoxidil is a topical drug, which must be applied directly to the scalp.

It comes in a vaporizer or dropper pipette. The preparation should be massaged into the skin using the fingers.

Experts recommend not overdoing the doses and following the doctor’s instructions to avoid irritation, flaking and redness. Two applications per day are generally recommended to respect absorption times. Some dermatologists consider that one application is sufficient to obtain the desired effects and not irritate the skin.

The Formulas present on the market

Minoxidil is present on the market:

    • In the form of foam: ideal for those with very short or shaved hair and very delicate skin as it does not contain glycol.
    • In the form of a lotion: liquid preparation using propylene glycol as a carrier.
    • Galenic preparations, mentioned above.

Side effects

The most common side effects caused by Minoxidil include:

    • Contact dermatitis due to an allergy to the components
    • Itching
    • Desquamation
    • Dryness of the skin;
    • Skin irritations;
    • Hair “greasy” appearance;
    • Eye irritation in case of contact;

More rarely:

    • Irregular heartbeat;
    • Headaches;
    • Water retention;
    • Bloating of hands and feet


Minoxidil 2% may be used by women. However, it should be avoided in cases of pregnancy and breastfeeding.

Minoxidil should also be avoided by individuals suffering from hypertension, heart disease and arrhythmias, due to its ability to reduce blood pressure.

Hair loss caused by Minoxidil

When experts speak of ‘Minoxidil-induced hair loss’, they are referring to a physiological phenomenon that is, however, of great concern to users of the product.

As Minoxidil synchronises the phases of the hair follicle’s life cycle, it is very likely that massive hair loss will occur, but will then be replaced by new hair with the start of a new anagen phase.

It is therefore quite normal to observe this phenomenon during the first few months of treatment. It is important not to be frightened and above all not to stop the treatment suddenly, as this would lead to a very severe effluvium.

How to stop using Minoxidil

If you decide to stop using Minoxidil, you should consult your specialist to find out the best way to stop taking the drug without experiencing a fall or very severe effluvium.

This can occur because, as already mentioned, Minoxidil tends to synchronise the growth of the follicles. If you stop taking the drug abruptly, all the follicles will simultaneously reach the telogen phase, i.e. the falling out phase.

Over time, the hair’s life cycle will return to normal and asynchronous.

It is, of course, possible to stop taking the medication. However, it is advisable to consult an expert who knows how to plan the discontinuation gradually, reducing the application of the product.

Professionals generally recommend reducing the doses within about three months, so that the follicles can gradually get used to the new condition.

Of course, once the application of the drug is discontinued, the beneficial effects will wear off.

If the application is stopped for only a few days, the follicles are not affected. It is, however, a good idea to avoid interruptions as much as possible.


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