Minoxidil Side Effects: What You Need to Know

Medically approved by
Dr Earim Chaudry
Last updated
20th November 2020

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Minoxidil is one of the most popular and effective ways to combat hair loss in men. It’s also one of the safest. However, as with all medications, Minoxidil can cause side effects. 

Minoxidil side effects can include irritation where the medication has been applied; dizziness, light-headedness, and headaches; and chest pain. These side effects of Minoxidil are rare and usually come from over-application. 

Side effects do not occur in the vast majority of cases. Minoxidil is the only licensed topical product for hair loss. It’s a medication that has been proven to stop — and even reverse — hair loss.

What Are the Side Effects of Minoxidil?

All medications have possible side effects, and Minoxidil (also known by the brand name Rogaine or Regaine) is no exception. 

However, this topical treatment has been rigorously tested and approved for medical use by the FDA – and the Minoxidil side effects that can occur are usually rare, temporary, and mild. 

These side effects include:

  • Skin irritation;
  • Dizziness, light-headedness, and headaches;
  • Drowsiness;
  • Swelling around the head, face, or hands;
  • Breast tenderness;
  • Changes in the colour, length, or thickness of body or facial hair;
  • Inflammation around the hair roots;
  • And irregular heartbeat or chest pain.

While this list might stop you in your tracks, it’s helpful to understand the reasons behind why you might experience some of these effects when using Minoxidil — and why it’s often nothing to worry about.

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Minoxidil Side Effects + Causes

1. Itchy Skin

The most common side effect of Minoxidil is irritated skin — either a mild rash or burning sensation — where the spray has been applied. This can be the result of a reaction either to the Minoxidil itself or to another substance, such as alcohol or propylene glycol, in the solution. It can also be a result of overapplying the treatment, so it’s always best to stick to the recommended dose.

Note: Do not use Minoxidil if the skin on your scalp (the application site) is already red, swollen, sore, or infected. Consult a healthcare professional if you’re worried about your symptoms.

2. Low Blood Pressure

The drug is a vasodilator, meaning Minoxidil lowers your blood pressure slightly. As a result, men can experience Minoxidil side effects including dizziness, drowsiness, and tiredness, as well as swelling around the head, face or hands. 

This is normal and is simply a reaction to your body’s adjustment to the changes in blood pressure. Other side effects of Minoxidil can include heart palpitations, chest pain, flushing, alterations to your vision, and nausea. These are not common and are usually the result of overuse, with an abnormally high amount of Minoxidil being absorbed by the body. 

3. Allergic Reactions

It is also possible that you can be allergic to Minoxidil, although again this is very rare. If you experience a severe skin rash, itching, hives, difficulty breathing, or sudden weight gain, stop using Minoxidil immediately and seek medical attention. These are serious side effects that might indicate an allergy.

How Common Are Minoxidil Side Effects?

In short, not very. And this assertion is backed by at least two randomized studies:

  • A 2002 study found that Minoxidil (at both 2% and 5% concentration) was well tolerated, with no evidence of systemic effects; and
  • A 2013 study observed no side effects over the course of three months of Minoxidil use by 100 men.

On the other hand, a 2019 review of Minoxidil and its use in hair disorders notes that while twice daily application of topical Minoxidil shows no systemic issues, side effects (however rare) are more likely to occur with a higher concentration of the topical Minoxidil solution.

Is It True That Minoxidil Causes Hair Loss?

Yes. Ironically, one of the more well-known side effects of Minoxidil is, in fact, hair loss

However, this is not so much a side effect as a part of the process by which the drug works. So, don’t worry – your hair is coming back! 

By bringing life back to your hair follicles, Minoxidil kickstarts the hair growth cycle through which the follicles pass. Shedding is part of each follicle’s cycle and any hair loss you notice is a natural step before your new hair’s regrowth. This is completely normal.

When taking Minoxidil, you may also see hair growth occur on different parts of your body, too. Most commonly, your facial hair may grow more than usual — but you can see increased body hair growth elsewhere at the same time. This is the result of the Minoxidil in your bloodstream.

Is Minoxidil Safe?

Despite the possible side effects, Minoxidil is safe in the vast majority of cases and it has been licensed for medical use. Generally, the benefits far outweigh the possible risks. Minoxidil promotes hair regrowth in the majority of cases and, when combined with Finasteride, is effective in 90% of men. 

Meanwhile, in most studies of Minoxidil, the frequency of side effects is not statistically significant. One study, with hundreds of participants, showed no cases of side effects over a three-month period.

If you’re interested in taking treatment for hair loss, at Manual we’ll ask you to take a short questionnaire first. This applies whether you are intending to take Minoxidil or Finasteride and is used to determine that the treatment is appropriate for you. You’ll be in safe hands.

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So, What Actually Happens When You Use Minoxidil?

We’ve covered the side effects of Minoxidil, and we’ve established that it’s a safe and effective method of treating hair loss in men. But what does it do to your body — and your hair? 

Unlike oral Finasteride, Minoxidil is generally applied topically, as a spray or foam. 

It has been found to produce hair regrowth in 60% of men. Minoxidil works as a vasodilator, and when applied as instructed, it dilates the blood vessels in your scalp and allows extra blood flow to the area. More blood means more oxygen and more nutrients — the things that your hair follicles need to stay healthy. 

It is not, however, an instant fix. As Minoxidil restarts the cycle of hair growth in your hair follicles, you will see results in six months to a year of continuous use. And as we mentioned earlier in this article, there is also hair shedding which can occur in the first few weeks, as the product brings your hair from the resting phase to the active growth phase.
You can read about how Minoxidil works in more detail here.

How Do You Apply Minoxidil?

Minoxidil should be applied twice a day usually, unless on a specialist personalised plan. As with all medications, if you miss an application, do not double-up with the next dose. The missed dose will have a minimal effect, but doubling-up on doses increases the chances that you’ll experience Minoxidil’s side effects. 

Be careful when you’re applying Minoxidil, too. Always read the drug information beforehand. Avoid contact with your eyes, nose, and mouth — and wash your hands thoroughly after application. If the solution gets into your eye, it can be very irritating.

A Word of Warning: Don’t Mix Minoxidil With Other Medications

The side effects of Minoxidil are rare. However, the adverse effects are made more likely when the drug is used with some other medications or by people who have particular medical conditions. 

Minoxidil is effective specifically for men experiencing male pattern baldness or hereditary hair loss. It should not be used in cases where hair loss is accompanied by scabs or lesions on the scalp. This increases the chances of the drug entering your bloodstream.

Minoxidil is generally not recommended for individuals with uncontrolled low or high blood pressure, or someone with heart problems (e.g. heart failure or heart disease). Often, the medicines to tackle these sorts of heart issues will lower your blood pressure (just like Minoxidil does). As a result, these drug interactions make the Minoxidil side effects like dizziness and fainting more likely. 

Key Takeaways…

Like all medicines, Minoxidil does have its potential side effects. These might include irritated skin, slight dizziness, and drowsiness. However, these occur rarely and, when they do, they are usually mild and temporary.

However, there are a few serious Minoxidil side effects. Changes in blood pressure can occur and your body may react to this in different ways. Consult a doctor or other medical advice if you are on other medications – or if you suspect you have an allergy to Minoxidil.

Minoxidil is entirely safe and is used by millions of men worldwide to treat male pattern baldness. If you’re experiencing hair loss, Minoxidil might be the best hair loss treatment for your hairline. The benefits certainly outweigh the risks. 

While we've ensured that everything you read on the Health Centre is medically reviewed and approved, information presented here is not intended to be a substitute for professional medical advice, diagnosis, or treatment. It should never be relied upon for specific medical advice. If you have any questions or concerns, please talk to your doctor.

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