Quick answer: minoxidil is a medicine that prolongs the hair’s growth phase and thickens hairs that are thinning, especially in androgenetic alopecia. It comes in topical and oral forms and should be prescribed and monitored by a doctor. In the first weeks it can increase shedding, results appear in 3 to 6 months and the effect depends on continuous use.
Few names come up as often in conversations about hair loss as minoxidil. It has decades of use and is among the most studied treatments for androgenetic alopecia — but it is also surrounded by questions: "will it make my hair fall out more?", "will I have to use it forever?", "can I take the tablet?". This guide exists so you arrive at your medical appointment well informed, not to replace it.
You will not find doses or prescriptions here. You will find what minoxidil does, what to expect and which precautions to discuss with your dermatologist.
What is minoxidil and how does it work on hair?
Minoxidil was originally developed as a blood-pressure medicine. Hair growth was observed as a side effect — and that led to its use for hair loss.
The exact mechanism is still being studied, but it is known to:
- prolong the anagen (growth) phase of the hair;
- enlarge miniaturised follicles, making hairs thicker;
- encourage the move from the resting phase into a new growth phase.
That is why it is used mostly in androgenetic alopecia, where follicles gradually shrink — see female pattern hair loss. In other situations, such as alopecia areata and some cases of effluvium, it may be used as an adjunct, at the doctor’s discretion.
Topical or oral minoxidil?
| Topical | Oral (low dose) | |
|---|---|---|
| How it is used | Solution or foam applied to the scalp | Tablet, at doses much lower than those used for blood pressure |
| Action | More local | Whole body |
| Advantages | Long track record, fewer systemic effects | Convenience, no change to hair routine |
| Watch-outs | Irritation, itching, oiliness, daily adherence | Blood pressure, heart rate, swelling, body hair |
| Who decides | Doctor | Doctor, after a health assessment |
Use of low-dose oral minoxidil has grown in recent years, and reviews such as Randolph and Tosti (2021), in the Journal of the American Academy of Dermatology, discuss its efficacy and safety. Even so, it is not for everyone and requires clinical assessment.
What is shedding and why is it alarming?
In the first 2 to 8 weeks of treatment, some people notice more hair falling out. This is known as shedding. The most accepted explanation: minoxidil pushes out hairs that were in the resting phase, making room for new growing hairs.
What to know:
- it is common and usually temporary;
- it tends to pass within a few weeks;
- it is not a sign that the treatment "isn’t working";
- tell your doctor about it, especially if it is heavy or prolonged.
Many people abandon treatment precisely at this stage. Knowing it may happen helps you stay calm.
How long until you see results?
The hair cycle is slow. In general:
- 2 to 8 weeks: possible shedding;
- 3 to 4 months: shedding tends to decrease;
- 4 to 6 months: first signs of thicker or new hairs;
- about 12 months: time to assess the real result with your doctor, ideally with standardised photos.
Not everyone responds the same way. Some respond well, some moderately and some hardly at all.
The most common side effects
According to MedlinePlus’s topical minoxidil entry, from the US National Library of Medicine, the effects most reported with the topical form include scalp irritation, itching and flaking. Other points to watch, always to discuss with your doctor:
- Irritation and contact dermatitis — sometimes from the formula’s vehicle rather than the minoxidil itself;
- Hair growth in unwanted areas, such as the face and forehead, more common with the oral form;
- Changes in hair colour or texture in some people;
- Dizziness, palpitations, swollen legs or shortness of breath — signs to see a doctor straight away, especially with the oral form;
- Toxicity to pets: cats are very sensitive to topical minoxidil; avoid contact with the product and with treated skin.
Minoxidil in women, men and beards
In women
It is one of the most used treatments for female pattern hair loss. Women tend to be more sensitive to facial hair growth, which weighs on the choice of form and strength. Irregular periods, acne and increased body hair call for hormonal investigation before or alongside treatment.
In men
For male pattern baldness, minoxidil is often combined with other medicines that act on the hormone DHT, at the doctor’s discretion. The response tends to be better on the top and crown than at the temples.
In the beard
Using it to fill beard gaps is popular online, but it should be guided by a doctor, because facial skin is more sensitive and effects on the body need to be considered. Results vary a lot from person to person, and some hairs may regress if use is stopped.
Who should not use it without careful assessment
- pregnant and breastfeeding women;
- people with heart disease, low blood pressure or uncontrolled high blood pressure;
- people with an inflamed, broken or sunburnt scalp;
- children, unless specifically indicated;
- anyone who has reacted to the product before.
Practical tips for topical minoxidil users
Always following your doctor’s guidance:
- Apply it to a dry scalp, not to the hair shafts;
- Wash your hands after applying;
- Avoid lying down with the product still wet, so it does not transfer to your pillow and face;
- Do not increase the amount on your own — more product does not mean more hair;
- Keep the washing routine your scalp needs; washing does not "remove the effect" when the advised interval is respected;
- Record progress with photos every 30 to 60 days, in the same light.
What about minoxidil bought without a prescription?
Some topical formulations are sold over the counter in some countries, and there are many compounded and imported products in circulation. The problem with using it on your own:
- the cause of your hair loss may not be androgenetic alopecia;
- strength and vehicle may not suit you;
- side effects can go unnoticed;
- shedding alarms people and leads them to quit.
Hair loss has many causes — see the most common in female hair loss: 9 causes. Treating the wrong cause wastes time.
Where does scalp therapy fit in?
Scalp therapy does not prescribe minoxidil or adjust doses. The hair therapist’s role is complementary:
- assessing the scalp and referring to a dermatologist;
- managing irritation, oiliness and flaking that make topical use harder;
- tracking progress with trichoscopy and standardised photos;
- supporting adherence by explaining shedding and the importance of continuity;
- advising on cuts and styling that make the most of volume during treatment.
Frequently asked questions
It can. In the first weeks, some people notice a temporary increase in shedding. This happens because hairs in the resting phase are pushed out by new growing hairs. It usually passes within a few weeks, but tell your doctor about it.
In general, minoxidil’s effect lasts only while it is used. When it is stopped, hairs that depended on the treatment tend to fall out over the following months. That is why starting and stopping should be decided with a dermatologist.
There is no single best option for everyone. Low-dose oral minoxidil has been used by dermatologists in selected cases and can be more practical, but it acts on the whole body and requires a risk assessment. Topical minoxidil acts more locally. The choice is a medical one.
It is not recommended during pregnancy or breastfeeding. Any hair-loss treatment during this period should be discussed with the obstetrician and dermatologist.
Medical treatment with close follow-up
If you are starting or thinking about starting minoxidil, having someone watch your scalp closely makes a difference. In the Hair & Scalp Therapy Consultation, I carry out trichoscopy, periodic photo records and a scalp-support protocol, always in partnership with your dermatologist and without promising results.
I want follow-up for my treatment →
A professional in the field? The Practical Trichology e-book explains how to support clients in medical treatment and where a hair therapist’s role ends.
Nelma Faleiro holds a specialisation in Cosmetic Trichology (Faculdades Oswaldo Cruz) and a degree in Visagism and Hair Therapy Technology from Anhembi Morumbi University, where she taught for 10 years. Educational content: it does not replace medical advice. Do not use medicines without a prescription.
