Side effects of minoxidil

Minoxidil is a medicine that's used to help prevent further hair loss and help hair regrowth in people with male and female pattern baldness (androgenic alopecia). This is the most common type of progressive hair loss, affecting about half of men over 50.

What is minoxidil?

Minoxidil was discovered by accident during trials for a high blood-pressure treatment, during which it showed signs of being able to regrow hair.

Minoxidil-based products are applied as a liquid or foam to the scalp. They work by increasing blood flow to the hair follicles, which stimulates and prolongs hair growth. Minoxidil products are available without a prescription and come in liquid or foam form, containing either a 5 percent or 2 percent concentration. They're not available on the NHS.

Minoxidil can be used by both men and women, but there are different products specifically designed for each.

What are the side effects of minoxidil?

As with all medicines, there can be potential side effects to taking minoxidil. While not everyone will experience them, there is a risk of the following side effects.

Common side effects

Common side effects include headaches, unwanted hair growth on body or face and itching.

Other side effects include:

Changes to the hair

One side effect is changes to the nature of newly-grown hair.

Hair loss

An uncommon side effect of minoxidil is increased hair loss, usually in the early stages of treatment.

Skin irritation (allergic contact dermatitis)

Minoxidil treatments are applied once or twice daily to the same patches of scalp, sometimes for long periods of time. Certain products contain a chemical called propylene glycol, which aids absorption. However, some people can react to this chemical.

If you have a reaction to minoxidil, stop using it and speak to your GP or pharmacist. For the full list of side effects, read the patient information leaflet.

Can anyone use minoxidil?

It's recommended that certain people do not use minoxidil hair loss products.

Those who should not use minoxidil include:

• Under 18s and over 65s

• Pregnant women

• Breastfeeding women

• People with high blood pressure

• People who have conditions which affect the scalp

• People with a shaved scalp

• Completely bald people

If you have a medical condition, or if you're not sure if minoxidil is suitable for you, speak to your pharmacist or GP before using it.

If you're taking any other medicines, you should speak to your pharmacist or visit your GP before using minoxidil. When combined with certain medicines, such as diltiazem or hydralazine, there is an increased risk of low blood pressure.

Next steps

• Speak with your GP or pharmacist if you're unsure whether minoxidil is suitable for you or not

• Do not use minoxidil if you are pregnant or breastfeeding

• Speak to your pharmacist or GP if you experience side effects whilst taking minoxidil