Minoxidil side effects to watch out for

Published on October 2, 2020
Updated on October 2, 2020
Man holding a white bottle prior to depositing a solution onto his fingertip
Minoxidil is considered to be completely safe for skin, so you can even apply it with your bare hands

You might have heard that certain hair loss products can cause some scary-sounding side effects. While side effects are certainly possible, treatments approved by the Food and Drug Administration (FDA) are thoroughly tested and are generally quite safe.

If fear of a bad reaction is preventing you from starting a hair loss treatment, you’ll be glad to know that different products have different side effects. Products like minoxidil do have side effects, but they are often considered to be much less serious compared to other hair loss treatments, like finasteride.

Hair loss treatments and their side effects

From supplements to lotions and medical devices, there are quite a few different treatments for hair loss you can choose from. Some of these products and therapies are approved by the FDA. Others might help support hair growth or improve hair thickness, but aren’t approved to treat specific hair loss conditions like male pattern baldness (androgenic alopecia) or alopecia areata.  

Out of the variety of hair loss treatments available, there are three products that the FDA has approved for male pattern hair loss: minoxidil, finasteride, and low-level laser therapy. While all of these hair loss products and treatments have side effects, their adverse effects are limited and have been tested rigorously by the FDA.

You may find that some treatments have more serious side effects compared to others, though. For example, finasteride is well known for causing negative sexual side effects. According to an article from the Journal of Mind and Medical Sciences, finasteride can decrease a person’s sex drive, cause erectile dysfunction, and may even lead to mental health problems.

In contrast, there aren’t any minoxidil side effects that can sexually affect you. In fact, minoxidil side effects are pretty mild compared to those of finasteride.


What are the side effects of minoxidil?

There are a variety of different reported side effects for minoxidil – but they are generally quite rare. According to studies in the Journal of the American Academy of Dermatology and Recent Patents on Inflammation & Allergy Drug Discovery, minoxidil side effects include:

  • Stinging or burning sensations after applying the product
  • Redness and irritation
  • Itchy scalp
  • Scaly scalp (like dandruff)
  • Dermatitis
  • Hypertrichosis, where hair growth occurs in areas other than just on your scalp

Out of all of these, the most common side effects – itchy or scaly scalps – are fairly mild. Other side effects, like hypertrichosis, are much less common. 

There are a handful of very rare side effects associated with minoxidil, as well. For example, some people with light hair might find that minoxidil affects their hair color, turning it slightly yellow or green. This isn’t so much of a minoxidil side effect, though. It’s more indicative of a cheap product or one that contains coloring agents.

Although allergies to hair loss treatments are rare, it’s also possible to be allergic to minoxidil. The FDA says you should talk to your doctor if you start experiencing swelling around your hands or feet, feel faint or dizzy, or have any chest pain. These can be signs of an allergy or a more serious health problem. 


Side effects can vary 

At the end of the day, finasteride might be more likely to cause sexual side effects, while minoxidil might be more likely to cause skin problems. However, you should be aware that side effects can vary.

While oral finasteride may cause problems like erectile dysfunction, researchers, like the ones in this study published in the Journal of Medical Association of Thailand have reported that a less concentrated finasteride lotion does not cause the same side effect. This finasteride lotion is intended to be used for male pattern hair loss alongside a minoxidil serum.

Unfortunately, finasteride lotion is still being tested by researchers and is not yet available to buy in stores. However, this study showed that changing finasteride from oral to topical and reducing the concentration of this medication could completely change its side effects.

Minoxidil products are not all created equal

Just like finasteride, oral minoxidil and topical minoxidil aren’t really the same when it comes to side effects. Oral minoxidil is more likely to cause side effects like hypertrichosis, while topical minoxidil is more likely to cause dermatitis and mild skin problems.

Similarly, many of the side effects associated with topical minoxidil are caused by a specific ingredient: propylene glycol. If you already know you’re allergic to propylene glycol, you may prefer foaming minoxidil products instead of minoxidil serums.

That’s one of the best aspects of minoxidil compared to other hair loss products: If you suddenly end up with a negative reaction, you can often just switch to a different formulation, concentration, or product type.


If you’re concerned about your hair loss treatment and its potential side effects, don’t be. There are many hair loss products you can choose from. Most people can find the product that works best for them after a bit of trial and error. 

At some point, a finasteride lotion with minimal side effects may be sold near you. But, for now, oral finasteride is likely to cause a wider range of side effects compared to minoxidil. 

Just remember: Not all products are created equal. If your doctor recommends a minoxidil pill or foam and you end up with unpleasant side effects, ask if you can switch to a minoxidil serum. You may even need to change the concentration of your product or find an alternative that uses different ingredients.

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.


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