Although Minoxidil (Rogaine) is usually safe, it may cause side effects like scalp discomfort, unexpected hair growth, or temporary hair shedding.

Rogaine is a brand name for minoxidil, the only topical ingredient approved by the Food and Drug Administration (FDA) for regrowing hair. Rogaine can treat hair loss from androgenetic alopecia, also known as male or female pattern hair loss (FPHL).

Researchers are still examining its ability to treat other hair loss conditions, like chemotherapy-related hair loss and alopecia areata.

About 40% of women have some degree of FPHL by the time they’re 50. This type of hair loss usually starts as a gradual thinning around the part of the hair and becomes wider with time.

FPHL is largely caused by genetics, and it’s thought that estrogen levels play a role because FPHL becomes more common after menopause.

Rogaine is generally considered a safe treatment, and complications are usually mild. Keep reading to learn about the side effects of Rogaine for women as well as alternative treatment options.

You’ll notice the language used to share stats and other data points can be binary, fluctuating between the use of “male” and “female” or “men” and “women.” While we typically avoid language like this, specificity is key when reporting on research participants and clinical findings.

Contact dermatitis on the scalp is the most common side effect when using Rogaine. Contact dermatitis usually occurs within minutes to hours after application. It causes symptoms such as:

Contact dermatitis

The first time you use Rogaine, apply it to a small part of your scalp and wait 24 hours to see if symptoms develop before using it over your entire head.

Rogaine can lead to unwanted hair growth on the face if the medication comes into contact with it.

Unwanted hair growth occurs more often in women than men, although it’s not clear why. Studies have reported unwanted hair growth in anywhere from 3% to 51% of female participants.

In very rare cases, you can develop generalized hypertrichosis, which is increased hair growth in areas not directly exposed to the treatment. It’s most common in adolescents and children.

Rogaine may cause a form of temporary hair loss called minoxidil-induced telogen effluvium.

Your hair cycles through four stages of growth:

  1. Anagen: the growing phase
  2. Catagen: transition phase
  3. Telogen: resting phase
  4. Exogen: shedding phase

Along with stimulating the growth phase, Rogaine can also shorten the resting phase, which leads to increased shedding. This shedding usually occurs 2 to 8 weeks after treatment starts. It generally lasts for 1.5 to 2 months, and is not a reason to stop taking Rogaine.

An older 2011 study found that hair shedding was reported in 17.5% of women who took a 2% solution of minoxidil twice daily and in 12.5% of women who took 5% minoxidil once daily.

FDA Black Box Warnings

This drug has black box warnings. Black box warnings are the most serious warnings the Food and Drug Administration (FDA) issues. They are designed to notify doctors and patients about serious drug effects that may be dangerous.

  • Chest pain warning: Rogaine can cause or worsen chest pain. It may also increase your heart rate. Your doctor may prescribe a beta-adrenergic blocking drug (beta-blockers) with Rogaine to help avoid this side effect. Let your doctor know immediately if you have new or worsening pain in the chest, arm, or shoulders.
  • Heart function warning: Rogaine can worsen existing heart problems. It can also cause poor heart function. Your doctor will monitor you for this and may prescribe medications, like diuretics (water pills) and beta-blockers along with Rogaine to help prevent any heart problems.
  • Proper usage warning: Minoxidil is a very strong blood pressure-lowering drug. If your doctor prescribes minoxidil to treat hypertension (high blood pressure), they doctor will only do so if you have already tried the maximum dose of a diuretic (water pill) and at least two other blood pressure drugs at the same time, with no improvement in your high blood pressure. Only start minoxidil while under your doctor’s close supervision.

For most people, Rogaine has an insignificant effect on blood pressure, but some individuals with hypertension who take antihypertensive medications may have concerns.

An older 2015 case study described a patient who developed low blood pressure after using a very strong minoxidil cream for 12 weeks. The man’s blood pressure returned to a normal range after discontinuing use of the cream.

It should be noted, however, that the preparation used in this study had more than twice the concentration of minoxidil compared to the over-the-counter foam.

The FDA lists Rogaine as a category C pregnancy drug. Drugs in this category haven’t undergone adequate human testing showing that they’re safe for fetal development, and animal studies suggest possible dangers.

Nursing women should also avoid using Rogaine due to its potential to enter breast milk.

Do not use Rogaine (minoxidil) if you are pregnant or breastfeeding. It may harm fetuses and young children.

Although it’s fairly rare, it’s possible to develop an allergic reaction to Rogaine. Allergy symptoms usually appear quickly and include:

It’s possible to be allergic to minoxidil itself or another ingredient found in Rogaine called propylene glycol. If you’re allergic to propylene glycol, you can try using the foam form of Rogaine that doesn’t contain this ingredient. If you’re allergic to minoxidil, you should cease this treatment altogether.

Studies have found that around 2% to 7% of women develop headaches after taking Rogaine.

A 2011 study found that about 3.5% of women developed heart palpitations, or a rapid heart rate. People with cardiovascular problems may want to talk with their doctor before taking Rogaine.

However, a 2024 retrospective multicenter study of individuals with hypertension or arrhythmia who take a low dose oral minoxidil found that participants had a similar experience to those who do not have hypertension or arrhythmia.

Other reported symptoms with an unknown incidence rate include:

As an oral medication, minoxidil is used to lower blood pressure. Usually, topically applied minoxidil has an insignificant effect on your blood pressure. However, if you’re taking diuretics or hypotensive medications, it can lead to low blood pressure that causes dizziness or fainting.

If you’re taking guanethidine to control your blood pressure, the FDA recommends being at a hospital the first time you use minoxidil to monitor changes in your blood pressure.

Rogaine and other brands of minoxidil are the only FDA-approved medications for treating hair loss in women.

The oral medication finasteride is FDA approved for men over the age of 18 to treat hair loss. While it’s commonly prescribed for female pattern hair loss (FPHL) in postmenopausal women, it’s generally not prescribed for premenopausal women. Finasteride should always be taken under the direction of a physician.

Finasteride is particularly dangerous for women who are pregnant, since it may harm male fetuses.

Other potential treatment options for hair loss in women include:

  • Targeting the underlying cause. In some cases, your hair loss may be caused by a treatable condition, like a thyroid hormone imbalance. Your doctor can help you figure out if your hair loss is genetic or has another cause.
  • Wearing wigs. Many women experiencing balding choose to wear a wig to cover their hair loss.
  • Making dietary changes. If your balding is caused by a nutrient deficiency, eating an overall healthy diet may help stimulate hair growth. Focus on foods high in protein, vitamin A, iron, B vitamins, and vitamin C.
  • Undergoing a hair transplant. Follicular unit transplantation and follicular unit extraction are two types of hair transplants that use follicles from one part of your scalp to cover balding areas in another.

Rogaine is available over the counter. Even so, if you’re experiencing hair loss, it’s a good idea to talk with your doctor before starting treatment. Your doctor can help you rule out other causes of hair loss that may be treatable, such as low thyroid hormone levels or a nutrient deficiency.

You should also visit your doctor if:

  • your hair loss is sudden
  • your head itches or burns
  • your hair is falling out in clumps
  • you have bald patches

Rogaine can help women treat genetic hair loss. In women, genetic hair loss usually manifests as a gradual thinning of the hair along the part.

Rogaine is generally considered safe, but for some people, it can cause side effects, such as scalp irritation, unwanted hair growth, or temporary shedding.

If you notice any of these symptoms or anything else concerning, contact your doctor right away.