Minoxidil is one of the world’s most popular hair growth medications, due to its high levels of safety and effectiveness [1]. However, so far, only the topical formulation has been FDA and MHRA-approved for treating androgenetic alopecia, while oral tablets can only be prescribed off-label for hair loss [2][3]. This raises questions about whether oral Minoxidil is safe for long-term use.
The good news is that this medication has been amply studied in all its forms and most scientists agree that low-dose oral Minoxidil is generally safe and well-tolerated [4][2]. However, in rare cases, it can have some serious systemic side effects. This article will tell you all about the risks of taking this treatment long-term, including:
Minoxidil was initially developed as a medication to treat high blood pressure. However, it soon revealed significant, unforeseen hair loss benefits in people using this treatment [3]. This property was carefully studied and in 1988, Minoxidil became the first FDA-approved hair loss treatment [5] (and went on to be approved by the MHRA as well).
However, this approval was only given for topical formulations. While most scientists and doctors deem low-dose oral Minoxidil tablets generally safe and effective for hair growth, they still carry a higher risk of systemic side effects. Only a small fraction of users opt for oral Minoxidil, as studies show little [6] to no [7] superior effectiveness compared to topical Minoxidil 5%.
Minoxidil is very effective against several types of alopecia. It has a proven track record of reducing hair shedding and improving hair density in male and female pattern baldness. Moreover, this medication is highly versatile and can be used off-label to help stimulate hair growth in many hair loss conditions, such as alopecia areata, chronic telogen effluvium, severe traction alopecia and more [8][1][9].
Minoxidil works for hair loss by dilating your small blood vessels (capillaries). This allows more blood to flow through them, bringing greater quantities of oxygen and nutrients to your hair follicles [1]. When they are better nourished, your follicles can stay in the anagen (growth) phase of your hair growth cycle for longer. They can also produce stronger, thicker, and healthier strands that can resist hair miniaturisation.
When you take oral Minoxidil, it dissolves in your stomach and enters your bloodstream, travelling to your scalp and improving your hair growth. This can make it reach your capillaries easily, but it can also lead to unwanted systemic side effects.
The safety profile of the low-dose oral Minoxidil used for hair loss has been studied extensively. This medication is largely safe and well-tolerated by most users [7][2]. Its adverse reactions are typically mild and temporary, often resolving within 3-4 weeks of onset [10].
However, oral Minoxidil can still cause some potentially severe side effects in a small subset of patients, especially at higher doses (over 1mg per day) [11]. Moreover, people with certain health issues should not take oral Minoxidil at all (to be discussed).
If you want to start taking oral Minoxidil, you will need a prescription from a trichologist, a dermatologist or your GP. They can determine whether this treatment is safe for you and does not interfere with your other medications or worsen any existing health conditions.
Oral Minoxidil travels through your bloodstream to reach your hair follicles. This means it can have systemic side effects that aren’t confined to your scalp, such as [2][8][3]:
Common oral Minoxidil side effects:
Very rare (but potentially serious) Minoxidil side effects:
Fortunately, low-dose oral Minoxidil side effects have been shown to diminish with time and/or a dose adjustment. They will normally resolve completely soon after treatment cessation[10]. There are no reported cases of permanent Minoxidil side effects.
A robust body of research shows that, for most users, oral Minoxidil is safe to take indefinitely and no specific side effects have been associated with prolonged use. In fact, research shows that long-term treatment compliance is better for oral than topical formulations [12], as the tablets are more convenient to use and do not normally produce Minoxidil scalp itching or a rash.
Yes, according to multiple studies, oral minoxidil can be safely used by women, albeit normally in lower doses than men [8]. Women have a higher risk of developing unwanted face and body hair and headaches than men.
However, this medication is not recommended in pregnancy or for breastfeeding mothers. Research shows that it can cause excessive foetal hair growth and can be secreted in breast milk, posing a risk to babies [8]. At this time, no studies show exactly what kind of harm (if any) low-dose oral Minoxidil can cause to babies. However, doctors recommend taking a cautious approach and pausing Minoxidil use throughout pregnancy and breastfeeding.
Patients with certain significant health problems are normally advised against taking low-dose oral Minoxidil for hair loss. If you are in any of these categories, make sure you get a doctor’s recommendation before trying this hair growth treatment [13][8][14]:
The available body of research largely agrees that topical minoxidil is safer than the oral variety [4]. That is because it is absorbed on the scalp and remains there to act on the capillaries that nourish your hair follicles. Only a negligible amount of compound enters your bloodstream, normally too low to cause systemic side effects.
So while topical minoxidil has its own specific set of adverse reactions (e.g. scalp itching, flaking, and irritation) [15][16], they are considerably milder and safer compared to oral medication [7].
Unfortunately, it is impossible to know ahead of time whether you will experience systemic side effects from your oral Minoxidil treatment. However, there are things you can do to reduce the chances of this happening:
If you would like to get the hair growth benefits of oral Minoxidil without being exposed to the systemic side effect risks, consider trying one or more of the following treatments.
Topical Minoxidil represents a safer alternative to the oral formulation, with mostly mild and temporary side effects. Moreover, recent research shows that topical and oral Minoxidil are similarly effective against female and male pattern baldness [11].
You can get the topical medication in a variety of forms, such as Minoxidil foam, solution, gel, or Minoxidil spray, for added convenience. And you only need to apply the Minoxidil to the thinning spots on your scalp, confining any adverse reactions to a smaller area.
Oral Finasteride has been linked to sexual and psychological dysfunction [17]. However, like topical Minoxidil, topical Finasteride is significantly safer, as it has extremely low chances of causing such systemic side effects [18]. In fact, it is likely safer than Minoxidil tablets and can produce excellent results in curbing hair thinning and improving hair density in people with androgenetic alopecia.
Just be aware that this treatment will not help other hair loss conditions, such as alopecia areata or telogen effluvium. Moreover, while more research is needed to prove this, premenopausal women may be negatively affected by topical Finasteride. Although the risks are much lower than with the oral formulation, it may still rarely cause foetal malformations or hormonal imbalances.
While it is one of the safest hair loss treatments available, this form of low-level laser therapy has proven effective against several types of alopecia [19][20]. It can help treat male and female pattern baldness, improve the symptoms of alopecia areata and regulate the hair growth cycle in telogen effluvium.
Red light therapy for hair growth uses red or near-infrared light that is absorbed into your scalp, increasing blood flow to your hair follicles and improving the functioning of your cell mitochondria. It only has minor side effects, such as scalp itching or tenderness [19][21]
Rosemary oil for hair is one of the best essential oils for hair growth. Research shows its effectiveness in treating androgenetic alopecia can be compared to that of Minoxidil 2% [22]. While its results may still be inferior to low-dose oral Minoxidil, its side effects are also very mild, usually minor scalp irritation or allergic reactions.
If you are experiencing hair loss but are concerned about the potential side effects of treatment, we are here to help you. Book a consultation with one of our dedicated trichologists at your earliest convenience. They will provide a thorough scalp and hair examination, diagnose the cause of your alopecia and walk you through your treatment options.
Our friendly hair doctors will help you weigh the risks and benefits of the available hair growth medications and therapies. This way, you can make an informed choice and get the safest and most effective hair loss treatment for men or hair loss treatment for women.
If you are interested in finding out more about the safety of oral Minoxidil in treating hair loss, don’t forget to check out the answers to these frequently asked questions.
Yes, research shows that the side effects of oral Minoxidil are dose-dependent [11]. So if you take 5mg of this medication per day, you are at a higher risk of developing systemic side effects than if you are only taking 1mg. However, keep in mind that this is generally a very safe and well-researched treatment, so the chances of severe adverse reactions are extremely low to begin with when it comes to the low doses used for hair loss treatment.
Taking low-dose oral Minoxidil – even long-term – should not harm a healthy person’s kidneys. However, if you are already experiencing advanced kidney disease, this treatment can be problematic, as it can cause sodium and water retention. While this is a very rare occurrence, people with serious kidney disease have an increased risk of fluid accumulation around the heart (pericardial effusion) and heart failure [8][12].
No, there is insufficient evidence of Minoxidil sexual side effects, regardless of the duration of use. None of the clinical trials performed on this medication report any such occurrence.
Another frequently prescribed medication for androgenetic alopecia, Finasteride, has indeed been linked to erectile dysfunction, low libido and ejaculatory dysfunction [17]. However, unlike Minoxidil, Finasteride works by lowering your dihydrotestosterone (DHT) levels. DHT is a male hormone that plays an important sexual and reproductive role. However, Minoxidil has no significant impact on your hormones and should not affect your sexual performance.
Minoxidil dread shed is a natural and temporary phenomenon which occurs a few weeks after starting treatment. As the medication starts to work, it shortens the resting phase of your hair growth cycle, pushing your hair follicles back into the growth phase sooner. This makes the hair that was supposed to fall out over a longer period start shedding at once, making it seem like your hair loss has worsened. However, in most cases, this dread shed will resolve itself after about a month and your hair will start growing back.
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