Oral Minoxidil for Hair Loss: Better than Topical?

Bonnke Arunga, MBBS

By    – Updated on October 22, 2020 – Reviewed by dermatologist Dr. Suneil Gandhi, MD

oral minoxidil for hair loss

Nowadays, the treatment for hair loss has become more popular, which was not the case a few decades ago, when active treatment for hair loss first started.

There are several treatment options for hair loss, and one of the most commonly used is minoxidil. Despite most people giving attention to the topical formulations, studies now show that oral minoxidil could also be effective in the treatment of hair loss.

History of oral minoxidil

When Upjohn Company, which later became part of Pfizer, developed minoxidil in the latter part of the 1950s, they had no intention to use it for treating hair loss. The medication was intended to treat ulcers.

However, animal-based studies revealed that it was not so effective in ulcer treatment. Instead, it was found to be a potent vasodilator (widening of blood vessels).

Due to its vasodilatory effects, the Food and Drug Administration (FDA) approved minoxidil for use in the treatment of high blood pressure in 1979. Although its effectiveness in lowering high blood pressure could not be rivaled by most of the drugs during that time, patients started presenting with unprecedented hair growth as a side effect of minoxidil.

Researchers soon realized that this side effect of minoxidil could have potential benefits in treating hair loss. They decided to research and develop a topical formulation of minoxidil which could be applied to the balding scalp.

A study that saw dense hair regrowth in 40% of the male participants eventually led to the approval of minoxidil lotion by the FDA in 1987 for hair loss treatment.

Evidence supporting the use of minoxidil

For several decades now, studies have shown that androgenetic alopecia is mainly a factor of hormonal imbalance, usually influenced by genetic predisposition. It is one of the most common causes of hair loss. This is the type of hair loss with the classic presentation of a receding hairline in men or central thinning on the scalp for women.

The major culprit for causing pattern hair loss is dihydrotestosterone, abbreviated as DHT. It is a metabolite of testosterone and has been implicated as the major cause of pattern hair loss due to three main reasons.

  • Balding scalps contain higher levels of DHT than the non-balding scalp.
  • Men who are deficient in DHT have lesser tendencies to go bald.
  • Men who do not produce testosterone have only a 5% chance of going bald, as evidenced by a 1951 study on castrated prisoners. However, it is worth noticing, that women secrete less testosterone than men, but still are subjects to androgenetic alopecia.

Thus, any medication that can reduce the levels of DHT in the body is a potential treatment option for hair loss. This is where medications such as Propecia® or topical finasteride, and supplements such as saw palmetto come in. But like all drugs, finasteride and saw palmetto have their shortcomings.

Minoxidil, on the other hand, has no influence on DHT and does not impact hormone production – but is one of the most effective treatment options for hair loss. So, how does it work? What is its mechanism according to studies?

Until now, fewer than 20 studies have been published on oral minoxidil for hair loss treatment. Since it has no effect on DHT and hormonal production, some of the mechanisms of hair regrowth by minoxidil are as follows.

Being a potent vasodilator, studies have shown that minoxidil actively increases blood flow and thus improves nutrient delivery to the hair follicles. Theoretically, more blood, more oxygen, and more nutrients delivered to the hair follicles stimulate hair growth.

The current hypothesis is that vasodilation and increased nutrient delivery causes shedding of follicles in the telogen phase and a subsequent replacement with thicker and fuller hair when follicles enter the anagen phase.

For minoxidil to work in the body, it is first converted to an active form called minoxidil sulfate by an enzyme called sulfotransferase, by a process called sulfation. As predicted by studies, the activity of sulfotransferase predicts the outcome of minoxidil treatment for hair loss.

Unfortunately, minoxidil for hair loss treatment works effectively for only about 30% to 40% of men and women because they lack sufficient activity of the enzyme sulfotransferase.

But for those who have a full activity of the enzyme, response to treatment is often impressive with a response rate higher than 90%. Oral minoxidil is activated in the liver and in the outer root sheath of hair follicles where sulfotransferase enzyme is also located.

Oral vs. topical minoxidil

Topical minoxidil has unrivaled favoritism among users over oral minoxidil. One of the reasons for this is the limited studies on the use of oral minoxidil for hair loss compared to topical minoxidil. Nevertheless, the available studies provide a glimpse of the possible differences between oral and topical minoxidil.


In a study conducted on 52 female subjects with female pattern hair loss, it was determined that 1 mg of oral minoxidil was equally as effective as 5% topical minoxidil applied daily. Ideally, the increase in hair density was predominant among the subjects using oral minoxidil. However, the difference was not statistically significant.

With topical minoxidil, higher dosages are likely to yield a better response and currently, there are options of even 10% and 15% minoxidil in the market. Unfortunately, higher doses also present with more side effects.

If the effectiveness of oral and topical minoxidil is the same, how do you decide on what to choose? Typically, topical minoxidil is safer than oral minoxidil when you are considering higher dosages. Therefore, the potential for side effects should inform your decision on what to use.


On average, the cost for oral minoxidil tablets of 2.5 mg is $40 for a supply of 100 tabs. However, the exact cost usually depends on the pharmacy you visit and the location of that pharmacy. On the other hand, the average cost of topical 5% minoxidil is $26 for a supply of 60 grams. This price varies depending on the percentage of minoxidil and the pharmacy from which you are making a purchase.

Ease of use

Oral minoxidil is generally easy to use because it is ideal for those who don’t prefer the messiness involved with some of the topical minoxidil solutions. Topical minoxidil, on the other hand, provides a localized approach to treatment because it is applied directly to the part where you want to achieve hair regrowth.


Since minoxidil is approved by the FDA for treating hair loss, the medication has been certified to be generally safe. However, there are a few side effects that should be expected and adequately managed when they occur. These side effects are more common with oral minoxidil than topical minoxidil.

Who are good candidates for oral minoxidil?

The effectiveness of oral minoxidil largely depends on the dosage. However, higher dosages are associated with adverse side effects. Therefore, you should evaluate the safety profile of oral minoxidil as an individual.

You are a good candidate for oral minoxidil if…

  • you are below the age of 40 years (effectiveness reduces as age increases)
  • you can swallow tablets
  • you have a healthy liver

You are a bad candidate for oral minoxidil if… 

  • you cannot swallow tablets
  • you have pre-existing medical conditions such as heart disease
  • you have a liver disease
  • you are pregnant (insufficient evidence for safety)
  • you are allergic to minoxidil

How to get the most out of oral minoxidil for hair loss treatment

If your goal is maximum hair regrowth or to restore healthier, fuller, and thicker hair, then you should do more than just using oral minoxidil. Here are some of the strategies to use:

1. Only use branded products 

If you are able to take advantage of that, use only branded products. That way you reduce the risk of using drugs that are not effective. For example, some popular brand names for topical minoxidil are Rogaine® and Lipogaine®, however, they do not provide minoxidil in an oral formulation.

Because hair loss is a booming niche with huge profits, patients are susceptible to predatory vendors whose products do not yield the desired benefits. In most cases, these unbranded products may end up presenting with worse side effects because the majority of them are not approved by the FDA.

2. Consider the benefits of combination therapy

To maximize hair loss treatment results, it is advised to use more than one strategy with different mechanisms of action. For instance, minoxidil does not affect the hormonal influence on hair loss.

On the other hand, finasteride is a potent DHT inhibitor. What is more, there are other options that can contribute to managing your hair loss such as low-level laser therapy.

If you have pattern hair loss, combination therapy of minoxidil and finasteride, or minoxidil and saw palmetto may significantly improve your results. However, you should do this only after consulting a certified doctor to ensure that your body can sustain the two oral medications simultaneously.

3. Know when to stop increasing the dosage

The general principle with minoxidil is that the higher the dosage, the greater the response. However, there is a certain dose limit beyond which an increase in dosage does not lead to a corresponding increase in dose-response.

As for oral minoxidil, usual doses for hair loss treatment vary in the range of 0.25 to 1.25 mg per day.

With significantly higher dosages, the benefits remain the same but the side effects increase significantly. If you are not careful, you may suffer from minoxidil toxicity. Consult your doctor on the best dosage plan for your hair loss.

Adverse reactions and side effects 

Unfortunately, oral minoxidil has wide and rapid tissue distribution. The major consequence of this pharmacologic process is that you may experience hair regrowth in unwanted areas of the body such as the face, chest, and legs. While this may be a dream come true for most men, it may be an unwanted side effect for women since most women dread body hair.

What is more oral minoxidil has some unique side effects and can even lower blood pressure if taken in high doses.

Additional side effects include:

  • dizziness
  • fast and irregular heartbeat
  • swelling of hands and feet
  • fatigue
  • weight gain
  • chest pain
  • fainting
  • difficulty in breathing (especially when lying down)

Interactions with other medications

Minoxidil can interact with other medications and either reduce their effectiveness or worsen their side effects. This is why you should be careful using oral minoxidil if you have a pre-existing medical condition for which you are receiving treatment.

While this article does not list all the drugs that interact with minoxidil, you should rely on your doctor’s advice before deciding on using oral minoxidil with another medication simultaneously. A few examples of drugs not to use with oral minoxidil are metronidazole, guanethidine, and disulfiram.


Oral minoxidil is an effective treatment for hair loss. More studies are required on whether it is equally effective as topical minoxidil. You can decide on which formulation to use depending on your convenience.

Note that in the event of overdose, oral minoxidil has severe side effects. This means that you should take oral minoxidil for hair loss only under the guidance of a certified medical professional.

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