Minoxidil Side Effects: What Women Should Know Before Starting Treatment

It’s completely normal to have questions about minoxidil side effects, whether you’re about to start or you’ve started taking it. Topical minoxidil is a licensed treatment for hair loss, while oral minoxidil is prescribed off-label for this purpose in the UK, under clinical supervision. Most side effects are usually mild and can often be managed at home.

Common side effects include unwanted facial hair and temporary weight gain, while other side effects may include changes to hair texture and short-term hair shedding. 

Topical minoxidil side effects

According to a 48-week randomised trial of women with hair loss, around 14.4% of women using minoxidil 5% solution get side effects.* These side effects are usually mild and can be managed easily at home for most people.

Important: You may notice some temporary hair shedding during the first 6 weeks of using minoxidil. This is a normal part of the treatment and happens as minoxidil shifts your hair into a new growth cycle. It usually settles as your hair growth cycle adjusts.

Common side effects

Common side effects (affecting up to 1 in 10 people) include:

• Headaches

• Mild scalp dryness, itching or sensitivity

• Light flaking or redness, particularly when first starting

• A temporary increase in hair shedding in the early stages

• Fine unwanted hair growth outside the scalp area if the product comes into contact with other areas

Oral (low-dose) minoxidil side effects

Oral minoxidil side effects are different from topical ones due to the amount of medication entering the blood. Very little topical minoxidil is absorbed by the skin, whereas oral minoxidil is absorbed through the stomach and affects the scalp from within the body.

Important: Oral minoxidil is not licensed for female hair loss in the UK; however, there is clinical evidence supporting its use in the treatment of hair loss. It may therefore be prescribed off-label under appropriate clinical supervision.

Common side effects

Common side effects (affecting up to 1 in 10 people) include:

• Mild increased fine hair growth, including unwanted facial hair

• Light-headedness/dizziness (this is why we advise taking it at night before bed)

• Mild swelling/fluid retention

• Palpitations/tachycardia

• Headache

Serious side effects - when to seek help

Most side effects of minoxidil are mild, but a small number of people experience more serious symptoms affecting the heart, breathing or circulation. Know what to watch for so you can act quickly if you need to.

Call 999 or go to A&E if you get:

• Chest pain, pressure or tightness

• Difficulty breathing or severe shortness of breath

• Fainting or nearly fainting

• Rapid or irregular heartbeat

• Swelling of the face, lips, tongue or throat

Stop taking minoxidil and contact a clinician (call 111 for advice) if you get:

• Shortness of breath, especially when lying flat

• Dizziness or light-headedness that doesn't go away

• Unusual tiredness or weakness

• Swelling of the legs, ankles, feet or abdomen

• A feeling of fullness or discomfort in the chest

• Fast, unexplained weight gain

• General itching, redness, or ongoing severe scalp inflammation

Does Minoxidil Cause Increased Hair Shedding?

For many women, this is the side effect that is the most worrying. Some people notice  increased shedding in the first few weeks of the treatment. Although this is a normal side effect of minoxidil, it is temporary, often minor and varies from person to person. It also means that the treatment is working, as old hairs fall to make way for new, healthier hair growth.

This may be surprising considering minoxidil is for treating hair loss and the idea of losing more hair, even temporarily, may be frustrating. The reason this increased hair shedding may happen is because of how the hair growth cycle works, so remember it is a normal part of the process; stay consistent with treatment, and hair regrowth will follow.

Does Minoxidil Cause Acne?

Minoxidil doesn’t have a clear link to acne, although topical minoxidil may cause spots on the scalp due to irritation. This is because minoxidil doesn’t have an effect on hormones in the same way that other hair loss treatments like finasteride do.

If you notice an increase in acne anywhere other than your scalp, it’s likely that it isn’t related to minoxidil. Instead, it could be due to other medications, hormone changes not caused by minoxidil or other products you’re using on the affected area.

Does Minoxidil Cause Unwanted Facial Hair Growth?

Around 1 in 25 women who use minoxidil 5% will get unwanted facial hair growth.* Even though minoxidil solution is topical (applied to the head) it may still cause hair growth in other places, either from contact with the skin or from a small amount being absorbed. This can be minimised by applying the product carefully to the intended treatment area and avoiding contact with the surrounding skin. If any product accidentally comes into contact with other areas, wipe it away promptly with a facial wipe or damp cloth to help reduce the risk of unwanted hair growth.

Unwanted facial hair is much more likely with oral minoxidil, affecting between 1 in 10 and 1 in 3 people.* The reason it’s more likely with tablets is that the medication enters your bloodstream and circulates throughout the body, whereas only a very small amount is absorbed through the skin when using topical minoxidil.

For hair loss, oral minoxidil is used at low doses, aiming to promote hair growth on the scalp while limiting the risk of unwanted hair growth elsewhere on the body. However, unwanted hair growth can still occur and may be more noticeable in some people than others. This can be managed at home with hair removal solutions such as shaving, waxing, hair removal creams or bleaching.

*Weichert M, et al. (2025). Efficacy and safety of minoxidil therapy: a systematic review and meta-analysis weighing the benefits against the risk of hypertrichosis

Does Minoxidil Cause Hair Colour Changes?

Minoxidil tablets may cause your hair to appear darker. This is because minoxidil causes your follicles to produce thicker hair that has more pigment in, which causes a darker colour. It also makes hair thicker, which may make it appear darker too.

This won’t affect existing hair, so your hair won’t suddenly change colour. It affects new hair as it grows, so the change may happen over time.

How to Reduce or Manage the Side Effects of Minoxidil

Since most side effects are mild, you may be able to manage them at home without needing to see a doctor in person. You can still message your Hers clinician at any time through the Hers App for extra advice and support.

When to get help from a doctor

If your side effects are bothering you or they aren’t improving, it may help to contact your Hers clinician via the Hers App, or see a doctor in person if you’re receiving treatment from another provider.

If you think you might have serious side effects, you may need to stop treatment and see a doctor as soon as possible or contact emergency medical services on 111 or 999.

FAQs

Does minoxidil affect female hormones?

No. Unlike hair loss treatments like finasteride or dutasteride, minoxidil does not affect hormones. This means it’s unlikely to cause hormone-related side effects, like acne, changes to sexual function or menstrual changes.

Can minoxidil make your face look puffy?

Yes. Facial puffiness, especially around the eyes, is a recognized side effect of minoxidil, more common with the oral pill than the topical foam or liquid. Minoxidil relaxes blood vessels, which can prompt the body to hold onto extra sodium and water; that fluid often shows up first as mild swelling in soft tissue like the face. It typically appears within the first one to three months of starting treatment and is usually mild and cosmetic. If swelling spreads beyond your face, comes with rapid weight gain, or is paired with shortness of breath, check in with your prescriber, since these can signal more significant fluid retention.

Can minoxidil cause permanent facial hair growth?

No. This can be a temporary side effect of minoxidil use but this isn’t a permanent change and it will usually stop once minoxidil treatment is discontinued. This may take around 1 to 6 months to go away after you stop treatment.