Oral minoxidil: does it work?

Millions of people experience hair loss. The most common treatment and prevention options are topical minoxidil foam or liquid that you spray on your scalp alone or combined with finasteride pills (also known as Propecia). But you can also take minoxidil in pill form to treat or prevent hair loss, even though it’s not usually the first choice for treatment.  

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Even though oral minoxidil isn’t usually the first treatment choice for hair loss, there are many reasons why a healthcare provider may recommend it. 

Topical minoxidil can cause irritation

A common side effect of topical minoxidil is irritation or rash on your scalp. If you experience that, your healthcare provider may recommend using oral minoxidil. 

But while oral minoxidil won’t cause the same type of localized irritation that topical minoxidil does, it’s not without its side effects. In clinical studies, the topical and oral versions were about equally effective at reducing or reversing hair loss, but the oral option was more likely to cause side effects (Ramos, 2020). 

The most common side effect of oral minoxidil is excess unwanted hair growth on other areas of the face and body (a condition called hypertrichosis). This side effect is typically more bothersome to women than men, so women taking minoxidil will typically get a lower dose than men. While hypertrichosis can affect about one in every 25 people who use topical minoxidil, the numbers rise to about one in every four people who use oral minoxidil (Ramos, 2020). 

Topical minoxidil might not be effective for everyone

Another reason to prescribe oral minoxidil is if topical minoxidil hasn’t worked. Topical minoxidil has to be applied consistently for about eight weeks to see results, and it may take as long as four months to see the full effects. Also, if you stop using it consistently, you’ll see any regrowth fall out again. But if you’ve used topical minoxidil as directed and didn’t get the expected results, a healthcare provider may recommend switching to the oral version. 

The reason oral minoxidil might work better for some people is that minoxidil is something called a “prodrug,” a form of the drug that needs to be activated by your body to work. Researchers believe that some people might not have the activating enzyme in their hair follicles, meaning that the topical medication wouldn’t be effective for them since it wouldn’t be activated. But the activating enzyme is actually present in our livers, so people who take the medication by mouth might see improvement in hair growth that they didn’t see when using the drug topically (Mirmirani, 2019). 

Applying topical minoxidil might be more difficult

Topical minoxidil needs to be applied twice a day for maximum effectiveness, and you’re not supposed to touch your hair/scalp, shower, or lie down for an hour after you use it. This can be a problem for some people who might find it difficult to stick with the regimen, and applying it sporadically won’t give you the same results as consistent use. 

Minoxidil in pill form might be a favorable option for people who prefer a daily pill to a twice-daily foam or liquid treatment.

Topical minoxidil can affect your hair texture

Some people report that topical minoxidil makes their hair feel dry or causes damage to the hair shaft, increasing the risk of breakage. This may be more common in people with longer hair. Taking oral minoxidil means you aren’t putting the medication directly on your hair. Instead, it works from the inside, so it doesn’t affect the texture or quality of your existing hair. 

Researchers have evaluated a wide range of studies on oral minoxidil for hair loss. Overall, they found that oral minoxidil works for treating hair loss, particularly for people with male- or female-pattern baldness, also known as androgenetic alopecia (Randolph, 2021).

One small study of 26 women compared oral minoxidil to topical minoxidil. The study showed that the groups saw similar results after about six months of treatment (Ramos, 2020). 

Since the mainstays of treatment for hair loss are typically topical minoxidil and oral finasteride, there’s less research on the effectiveness of oral minoxidil for combatting hair loss. That said, the research available shows it works for many people. 

And while researchers have emphasized that a larger scale trial would be necessary to better understand dosing and safety, oral minoxidil treatment may work for other causes of hair loss. These include conditions like telogen effluvium, loose anagen hair syndrome, monilethrix, alopecia areata, and hair loss from cancer treatment.

Still, it’s an off-label use for the medication, meaning that it’s not explicitly approved by the FDA for the treatment of hair loss, though healthcare providers can use their medical judgment to prescribe it if they think it’s the right treatment. (The FDA-approved application of oral minoxidil is for treating high blood pressure).

When used in lower dosages, side effects are typically minimal, but as dosages increase, side effects get more frequent and include unwanted hair growth (hypertrichosis), low blood pressure (hypotension), and swelling in the legs (edema), among others (Randolph, 2021). 

• Excessive hair growth (hypertrichosis): Because oral minoxidil reaches the whole body, as opposed to topical minoxidil which you apply just on the scalp, the most common side effect is unwanted hair growth in other areas. The complaint is more common among women than men but may affect as many as one in four people. It’s also more common at higher doses over 5 mg per day than at lower doses. According to one study, one in 20 women decided to stop treatment due to excessive unwanted hair growth (Vañó-Galván, 2021).   

• Initial hair loss or shedding: Because of how minoxidil works, many people report experiencing increased hair loss during the first six weeks of use before seeing improved hair growth. This is true for both oral and topical treatment. While this can be concerning for someone already worried about their hair thinning, it’s a well-known phenomenon and typically resolves after a month as the new hair grows in. 

• Headaches: One in 10 people experience headaches that typically improve over time. 

• Dizziness and low blood pressure: Oral minoxidil, at higher doses, is typically used as a treatment for high blood pressure (hypertension). While the low doses usually prescribed for hair loss aren’t supposed to affect a person’s blood pressure, about one in 10 users report symptoms of low blood pressure. These symptoms include lightheadedness or dizziness, especially when sitting up or standing up quickly. Let your healthcare provider know if you are taking any other medications, particularly those used to treat high blood pressure (like diuretics [water pills] or other treatments for hypertension). 

There are other, less common side effects of taking minoxidil by mouth. Tell your healthcare provider or pharmacist about all the medications and supplements you are taking, any health conditions you have or have had in the past, and any side effects you notice from taking the medication. 

Oral minoxidil (available under the brand name Loniten) is a prescription medication available in dosages of 2.5 mg, 5 mg, and 10 mg tablets and is typically prescribed to treat high blood pressure. Most studies on using this drug for hair loss look at lower dosages, though the most effective dosage for maximum benefit and minimal side effects haven’t been established. 

One study compared 1 mg of oral minoxidil daily for hair loss in women to 5% topical finasteride solution and found the two treatments to be equally effective (Ramos, 2020). A lower dose may be effective and will likely cause fewer side effects in women, while men may tolerate a higher dose. Providers can adjust dosages by prescribing half a pill or alternating dosage days, so you take the medication one day and skip it the next. Your healthcare provider will decide whether oral minoxidil is right for you and what dosage you should receive. 

Oral minoxidil for hair loss is generally prescribed at a lower dose than when used to treat high blood pressure (hypertension). Still, there are certain circumstances in which even low-dose minoxidil can be dangerous. These include: 

• If you have ever had an allergic reaction to oral minoxidil in the past. Note that if you have had an allergic reaction to topical minoxidil, oral minoxidil still might be a safe treatment option, but your healthcare provider will make that decision (Thearinou, 2020)

• Heart conditions, such as narrowing of the mitral valve (mitral stenosis), recent heart attack or chest pain (angina), enlarged left heart muscle (LVH), or heart failure. 

• Liver problems

• Low blood pressure

Minoxidil, whether as a pill or a topical treatment, doesn’t treat the cause of hair loss and is only effective for as long as you use it. If you stop using the treatment, any hair re-growth you experienced will go away.

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Current version

March 29, 2022

Written by

Health Guide Team

Fact checked by

Yael Cooperman, MD

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About the medical reviewer

Yael Cooperman, MD, Ro

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.