Topical minoxidil is a treatment for hair loss and hair loss-related conditions, such as alopecia. Although it is available over the counter, people should carefully consider the side effects before using this treatment.

This article discusses what minoxidil is and how it works. It also provides information on how to use this treatment and the possible side effects.

Scientists originally designed minoxidil as a treatment for high blood pressure, and doctors may still prescribe the oral form of the drug for people with severe hypertension.

In 1987, scientists developed a topical minoxidil solution that is suitable for treating hair loss in both males and females. The solution is available in either a 2% or 5% concentration. The brand names for topical minoxidil are Rogaine and Theroxidil.

Minoxidil and finasteride (Proscar and Propecia), another drug that prevents hair loss, are the only drugs that the Food and Drug Administration (FDA) has approved as treatments for hair loss in males. Research shows that these two drugs are up to 60% effective in preventing hair loss and encouraging hair growth.

Learn more about home remedies for hair growth.

A person applies minoxidil directly to their head in the form of either a solution or a foam.

According to a 2019 review, compared with minoxidil solution, minoxidil foam allows for easier penetration of the drug, increased delivery of the active ingredient, and reduced irritation to the scalp.

A scalp enzyme called sulfotransferase converts the minoxidil into a salt called minoxidil sulfate. It works by shortening the telogen, or resting, phase of the hair and causes the hair to enter the anagen or growing stage. There is some evidence that minoxidil can increase the thickness of the hair.

Learn more about the stages of hair growth.

Minoxidil does not cross the blood-brain barrier, and a person’s kidneys filter 95% of this drug within 4 days.

People may not notice any difference in their hair until they use minoxidil for at least 8 weeks.

A person can purchase minoxidil without a prescription. However, a doctor may recommend minoxidil if a person presents with hair loss.

Minoxidil is most effective for people under the age of 40 years whose hair loss is recent. The drug does not have any effect on receding hairlines.

Minoxidil comes in the form of a liquid solution or foam, and people usually apply it twice a day. A person should ensure that their scalp and hair are dry and that their scalp is not sunburnt.

It is important to read all instructions carefully. The manufacturer will state the correct dosage, which a person should never exceed.

People usually apply minoxidil using a pipette or a spray. They should avoid putting this drug on any part of the body other than the scalp and should not ingest it.

If the minoxidil comes into contact with the eyes or skin, a person should wash the area with cool water. If the area becomes irritated, they should call a doctor.

A person should contact their doctor if they experience an itchy, dry, scaly, irritated, or burning scalp after applying minoxidil.

If a person experiences any of the following side effects, they should seek emergency attention

If a person experiences any severe side effects, they or their doctor can report the symptoms to MedWatch, the FDA’s safety information and adverse event reporting program.


A person should speak with a doctor or pharmacist before taking minoxidil if they:

  • have an allergy to any of the ingredients in minoxidil
  • are taking any prescription or nonprescription medications, especially blood pressure drugs
  • are taking any vitamins
  • have or have had heart, kidney, liver, or scalp disease
  • are pregnant or breastfeeding

The use of minoxidil may also make a person’s skin more sensitive to sunlight. Therefore, it is best to avoid direct sunlight and wear protective clothing, sunscreen, and sunglasses when sun exposure is unavoidable.

Anyone who is taking any prescription or nonprescription medications or any supplements should speak with a doctor or pharmacist to ensure that it is safe for them to use minoxidil.

Minoxidil is a vasodilator, which means that it lowers blood pressure. Using minoxidil with other vasodilators, such as blood pressure medication or erectile dysfunction drugs, can be dangerous. A person should not use minoxidil with another vasodilator unless a doctor recommends it.

The following are some of the pros and cons of minoxidil:


  • topical minoxidil can be effective in treating hair loss
  • available without a prescription
  • suitable for males and females


  • not suitable for people who take vasodilators
  • works best for people under 40 years of age
  • does not treat receding hairlines
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Below, we provide the answers to some frequently asked questions about minoxidil.

Does minoxidil regrow all hair?

The effectiveness of minoxidil may vary among individuals. Although minoxidil can slow down and prevent hair loss, the amount of hair regrowth will vary.

Minoxidil is not a cure for hair loss. Once a person stops using this treatment, the body will most likely shed any new hair.

Can I leave minoxidil on during the night?

A person should use minoxidil twice a day, usually with a 12-hour interval between applications. However, a person should follow the manufacturer’s instructions to ensure that they are using the treatment correctly.

It is fine to leave minoxidil on during the night. However, a person should ensure that the minoxidil is completely dry before going to bed to prevent the treatment from rubbing off onto the pillow.

Is minoxidil safe for long-term use?

Minoxidil is safe for long-term use as long as a person never exceeds the recommended dosage.

A person should keep a list of all prescription drugs, nonprescription medications, and supplements they are using and take this with them when they see a doctor or go to the hospital. It is important for a medical professional to know which medications a person is taking to ensure that there are no adverse drug interactions.

Topical minoxidil is a treatment for hair loss in males and females. When a person uses this drug with finasteride, it can be up to 60% effective in preventing hair loss and encouraging new hair growth.

Topical minoxidil does not require a prescription. However, a person should inform their doctor or pharmacist of any other prescription or nonprescription medications they are using before purchasing minoxidil. If a person experiences any side effects, they should stop using the drug immediately and speak with a medical professional.