Minoxidil Side Effects: Dermatologist Explains What to Expect and When to Worry

Minoxidil is very popular and often used for treating hair loss for a reason, as it works for many. However, as with any drug, it has its side effects. They are mostly non-severe and treatable, but some are important to be aware of beforehand. So what can you expect when you use minoxidil, and when does a side effect become a serious medical condition? Here's what a dermatologist has to say.

What Are the Common Side Effects of Topical Minoxidil?

Dr Chandani Jain Gupta, Dermatologist and Aesthetic Physician at Elantis Healthcare, New Delhi, explains that most side effects of topical minoxidil are mild. Some of the symptoms include: 

• Itching, dryness, redness, or flaking of the scalp, which cannot be blamed on the drug itself, but is likely to be due to the propylene glycol in the solution.
• A first shedding period in the first two to six weeks, when old hair is pushed out to accommodate the growth of new hair,
• Raised hair that grows outside the hairline on the face, neck or head if it spreads outside the hairline on the face, neck or head
• Headaches and mild dizziness (these are less common)

According to the International Society of Hair Restoration Surgery (ISHRS), topical minoxidil mainly causes skin redness and irritation, with headaches, palpitations, or dizziness reported rarely. 

What Side Effects Come With Oral Minoxidil?

Dr Gupta says that the side-effect profile of low-dose oral minoxidil is slightly different to the topical version, which is becoming more popular for hair loss.

• The oral route is more likely to cause hypertrichosis (excessive amounts of hair on the body, arms or face) than the topical route.
• Mild swelling, often in the ankles or feet, and/or fluid retention.
• Faintness or rapid pulse (particularly at the beginning of treatment)
• Headaches and mild dizziness (less common)

However, according to ISHRS, the oral form of minoxidil also has a slightly broader side effect list, such as palpitations, dizziness, low blood pressure, chest pain, headaches, and leg swelling.  

Are There More Serious Side Effects to Watch For?

While uncommon, Dr Gupta explains that some side effects are more serious and shouldn't be ignored:

• Allergic contact dermatitis is manifested as persistent itching, redness, swelling or blistering at the application site.
• A marked decrease in blood pressure, loss of consciousness or a fast heart rate is more relevant to the oral route.
• Shortness of breath or fast heart rate
• Weight gain or swelling of hands and face (fluid retention)
• Vision changes, though this is rare and mostly reported with high-dose oral use

When Should Minoxidil Side Effects Be a Cause for Concern?

According to a 2024 study in Hair Transplant Forum International, researchers looked at 42 patients aged 60 and above taking oral minoxidil for hair loss. Only 19% experienced side effects, mostly facial or body hair growth in unwanted areas. Most issues were managed simply through lower doses, raising the legs, or reducing salt intake. No serious problems came up, though the study still advises caution for older patients on multiple blood pressure medicines.

But knowing when to visit a doctor for a symptom may be tricky, particularly as some shedding and irritation may be expected early on. Dr Gupta explains simple scenarios when it's advisable to seek medical advice:

• If initial shedding continues beyond two weeks without any sign of new growth
• If no improvement is seen after four months of consistent use, the treatment may need reassessing
• If scalp irritation, itching, or redness is severe or doesn't settle, since this could point to an allergic reaction
• If there's chest pain, a rapid or irregular heartbeat, fainting, or severe dizziness, especially with oral use, which needs prompt medical attention rather than a wait-and-watch approach
• If there's noticeable swelling in the hands, feet, or face, or sudden weight gain, signalling fluid retention that needs medical review
• If excess hair growth spreads to unwanted areas like the face and becomes distressing or keeps worsening

How Can You Reduce the Risk of Side Effects?

• Always use the lowest effective dose or strength, and only raise the dose as directed by medical advice.
• Use topical minoxidil as directed and don't go over the recommended dosages
• Thoroughly wash your hands after applying, and do not spread it unintentionally on eyes, broken skin or other parts of the body.
• If you are likely to suffer from contact irritation, select formulations with less propylene glycol, as foam formulations tend to have less propylene glycol than liquid formulations.
• A baseline blood pressure measurement should be taken prior to initiating oral minoxidil use and then periodically, particularly during the first weeks of use.
• Do not use minoxidil with other drugs to treat high blood pressure unless they are prescribed by a doctor.
• Specify the treatment time. It is normal to shed in the initial stage of treatment, and do not worry if it happens, or stop too early, but monitor and report if there is no improvement at month 4.
• Oral minoxidil should always be taken with the advice of a dermatologist and never prescribed without advice.

ALSO READ- Is Your City’s Water The Secret Reason For Your Hair Fall? How Hard vs Soft Water Affects Your Tresses

Conclusion

While Minoxidil may work for hair loss, it is important to know the side effects, including both common and rare ones, so you can use it safely and realise when it is time for a doctor's visit. Dr Gupta points out that it is much easier to detect and deal with any problems, if they arise, when treatment is started under proper medical supervision and not by self-prescribing.