Minoxidil Side Effects And How To Avoid Them - SingleCare

Key takeaways

• Minoxidil is used topically to treat hair loss and is available over the counter. Minoxidil is also an oral prescription drug used to manage high blood pressure that is causing symptoms or cannot be managed with other medications.

• Common side effects of topical minoxidil include scalp itching, dryness, and irritation. Common side effects of oral minoxidil include nausea, vomiting, headache, breast tenderness, and increased fine body hair.

• For oral minoxidil, it is important to follow your healthcare provider’s directions on how to take it, as well as taking a diuretic and beta blocker. Keep all follow-up appointments, as you will need to be closely monitored.

In this article:

• Most common side effects of minoxidil
• Serious side effects of Minoxidil
• Side effects of oral vs. topical minoxidil
• Side effects of minoxidil for women vs. men
• How long do minoxidil side effects last?
• Minoxidil long-term side effects
• Minoxidil side effects after stopping
• Safety measures while using minoxidil
• What to do if you miss a dose of minoxidil
• Expert takeaway

In this article

• Most common side effects of minoxidil
• Serious side effects of Minoxidil
• Side effects of oral vs. topical minoxidil
• Side effects of minoxidil for women vs. men
• How long do minoxidil side effects last?
• Minoxidil long-term side effects
• Minoxidil side effects after stopping
• Safety measures while using minoxidil
• What to do if you miss a dose of minoxidil
• Expert takeaway

You’ve likely heard of minoxidil, commonly known by the brand name Rogaine. This topical product is available over the counter to treat hair loss in both men and women. What you might not know is that minoxidil, when taken by mouth, can also treat hypertension (high blood pressure) and prevent complications like kidney and heart failure, stroke, and heart attack. If you are using minoxidil, whether topically for hair loss or orally for blood pressure, you’ll want to know what side effects to expect.

Most common side effects of minoxidil

Topical minoxidil

The most common side effects of topical minoxidil occur on the scalp and may include:

• Itching
• Dryness
• Scaling or flaking
• Irritation
• Burning

Oral minoxidil

The most common side effects of oral minoxidil are: 

• Nausea and vomiting
• Headache
• Breast tenderness
• Increased size or darkness of fine body hair

Serious side effects of Minoxidil

As with any drug, minoxidil can cause serious allergic reactions. You should get emergency medical help if you have symptoms of an allergic reaction, such as hives, trouble breathing, or swallowing, or swelling of the face, lips, tongue, or throat. 

Your healthcare provider will discuss other possible serious side effects with you before you take oral minoxidil, and tell you what to look for. You will need to call your healthcare provider right away if you have any of the following serious effects:

• A heart rate that increases by 20 beats or more over your usual pulse
• A rapid weight gain of more than five pounds, or swelling in the face, hands, ankles, or stomach
• Trouble breathing, especially when you lie down
• New or worse pain in the chest, arm, or shoulder, or severe indigestion
• Dizziness, lightheadedness, or fainting

Side effects of oral vs. topical minoxidil

Using topical minoxidil solution or foam may cause side effects on the scalp, such as itching, dryness, and irritation. Although rare, people who experience any of the following symptoms should get emergency medical help: weight gain, swelling, trouble breathing, fast heartbeat, chest pain, or lightheadedness.

With oral minoxidil, side effects can occur throughout the body, with the most common side effects including nausea, vomiting, headache, breast tenderness, and increased fine body hair. 

In clinical studies, about 80% of people taking oral minoxidil reported having longer, thicker, or darker body hair, known as hypertrichosis. This side effect usually begins within the first three to six weeks after starting minoxidil and typically first appears as facial hair. Later, hair may appear on the back, arms, legs, and scalp. Talk to your healthcare provider if this is a concern. 

Side effects of minoxidil for women vs. men

Women and men who use minoxidil topically for hair growth can expect similar scalp-related side effects. 

When taking minoxidil by mouth for high blood pressure, as mentioned above, excessive hair growth may occur as a side effect. The prescribing information notes that this may be especially bothersome in women, although it can be managed by shaving or other hair removal processes. If this is a concern, you should talk to your healthcare provider. 

Also, if you are pregnant or planning to become pregnant, consult your provider for medical advice before using minoxidil. Women who are breastfeeding should not use oral minoxidil and should check with a healthcare provider about the use of minoxidil topical solution or foam formulations. 

How long do minoxidil side effects last?

If you are using topical minoxidil and experience scalp-related side effects, check with your healthcare provider. Depending on the severity, they may recommend that you stop using minoxidil temporarily, use it less often, or try a different product. 

For oral minoxidil, mild side effects like nausea and headache may go away as your body adjusts to the medication. With oral minoxidil, you will be taking other medications, such as a water pill and beta blocker, that also have side effects. Talk with your healthcare provider about what kind of side effects to expect and how long they should last based on your individualized treatment plan. 

Minoxidil long-term side effects

Some healthcare providers prescribe low-dose oral minoxidil (LDOM) off-label (for a use that’s not approved by the Food and Drug Administration). LDOM may be used for various types of hair loss, including male androgenetic alopecia and female-pattern hair loss. In these individuals, it is usually safe to take LDOM long-term if side effects are not bothersome. The most common side effects in people who take LDOM are excessive hair growth and cardiovascular symptoms. 

For people who take minoxidil to treat high blood pressure, long-term use is generally required to achieve and maintain desired results. Side effects, like excessive hair growth, can often be managed with shaving or other hair removal methods.

Minoxidil side effects after stopping

If you are using topical minoxidil for hair loss, and you stop using it, the effects on hair regrowth will stop. Side effects related to the scalp should go away. 

You should not stop taking oral minoxidil for blood pressure unless advised by your healthcare provider. If your provider advises you to stop taking it, you may notice the following:

• If your provider advises you to temporarily stop taking minoxidil due to fluid retention, this should resolve within several days of stopping. Your provider will advise you on resuming treatment. 
• Excess hair growth will gradually stop, but it may take anywhere from one to six months.
• Minoxidil may affect your EKG heart test. This occurs in about 60% of people who take it. These changes often disappear in people who continue treatment as well as those who are advised to stop taking minoxidil. EKG changes do not typically cause symptoms or any other indications of heart damage.

Safety measures while using minoxidil

Minoxidil is not safe for everyone. Before using minoxidil, tell your healthcare provider about all of your medical conditions, and be sure to tell them if you are pregnant, planning to become pregnant, or breastfeeding. You should not use minoxidil if you are breastfeeding. If you are pregnant or planning to become pregnant, your healthcare provider can give you medical advice regarding the use of minoxidil.

You should not use minoxidil if you are allergic to minoxidil or any ingredient in the medication. People with an adrenal gland tumor called pheochromocytoma should not use minoxidil. 

Topical minoxidil products intended for use in males should not be used in females. These topical products should not be used by anyone under 18 years old. If you have any of the following symptoms, you should not use topical minoxidil and instead seek medical advice:

• Sudden or patchy hair loss
• Hair loss due to an unknown cause
• Hair loss after giving birth
• Scalp infections or swelling 

Oral minoxidil has a boxed warning, which is the most serious warning required by the FDA. It states that minoxidil tablets are very strong in lowering blood pressure and can cause serious side effects. Minoxidil should only be used in people with hypertension that is not controlled on the highest doses of a diuretic and two other blood pressure medications. People who take minoxidil should be closely monitored and should also take a diuretic and a beta blocker. Your healthcare provider will prescribe these medications and tell you how to take them. Follow these instructions carefully, as well as any other recommendations on dietary or lifestyle changes, and keep all follow-up appointments. 

Minoxidil is not a controlled substance and is not habit-forming. Always follow your healthcare provider’s instructions for use and do not stop taking minoxidil abruptly, unless directed by your provider.  

If you (or someone else) may have taken too much minoxidil, call Poison Control at 1-800-222-1222. If the person cannot wake up or has a seizure, call 911. 

What to do if you miss a dose of minoxidil

• If you are using topical minoxidil and you forget to apply a dose, you can skip the missed dose and continue with your next application. You should not apply extra or double doses to make up for a missed one. 
• If you are taking oral minoxidil and you miss a dose, take it as soon as you remember. But if it is almost time for your next dose, you can skip the missed dose and continue with your next dose at the regular time. Do not take double or extra doses to make up for a missed dose. If you miss a dose and you are not sure what to do, you can check with your healthcare professional. 

Expert takeaway 

All drugs come with potential warnings and side effects, and oral minoxidil is no different. If you are taking this medication for high blood pressure, your healthcare provider has carefully determined that the possible benefits outweigh the risks and is an appropriate medication for you. 

“Your healthcare provider will review how and when to monitor your blood pressure, heart rate, and weight while taking oral minoxidil,” says Karen Berger, Pharm.D., member of the SingleCare Medical Board. “It is important to follow these instructions closely and report any changes to your provider right away.”

If you are considering using topical minoxidil for hair loss, check with your healthcare provider first, as they may need to determine the reason for your hair loss and order testing. Topical minoxidil is usually well tolerated, though, with most side effects occurring on the scalp. 

Sources

• Minoxidil, DailyMed (2024)
• Minoxidil, MedlinePlus (2018)
• Minoxidil topical, MedlinePlus (2018)
• Minoxidil, StatPearls (2023)
• Low-dose oral minoxidil for alopecia: A comprehensive review, Skin Appendage Disorders (2023)

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