Side Effects from Hair Loss Medications:

Side Effects from Hair Loss Medications: What is the Chance?

Today, I’d like to review my personal view on medication and treatment-related side effects.


1.     Every single treatment has ‘potential’ adverse effects. (No treatment is risk-free).

Every treatment for hair loss has potential side effects. There is no treatment on the planet that is side effect free. How do I know that? Well, studies have shown that even patients using “placebo” treatments for their hair loss report side effects. This teaches us that any time a patient uses a treatment they have a chance to experience a side effect. Whether it’s a true side effect or not is sometimes challenging to decipher but a topic for another article.


2.     No medication or treatment for hair loss should ever be prescribed or used without patients understanding the “most common" adverse events

It is critically important for patients to understand the "most common" side effects of a treatment. The purpose of delivering such information to patients is to help them with informed consent.  A patient should only use a mediation if they feel that the benefits of using the medication are greater than the potential risks. It is the responsibility of the physician to transfer information about both the benefits and the risks to the patient so that the patient can offer their informed consent.


3.     It is not possible to explain all the potential side effects of a medication.

Despite the important role that we as physicians have in telling our patients about the side effects of medications, it is important for patients to be aware that a given presciber can not communicate the entire list of side effects that have ever been reported. However, it is imperative for the prescriber to advice on the most common ones. 

Take for example, the oral medication doxycycline. In the hair clinic, doxycycline is used for the treatment of scarring alopecia, folliculitis and a variety of other inflammatory and infectious conditions. A patient who is deciding on whether to use doxycycline or not should be made aware of the most common side effects including gastrointestinal upset, nausea, headaches, increased chance of yeast infections in women.

However, rare side effects are possible as well. For example, every year a small number of users of doxycycline around the world develop serious allergic skin reactions. It would be highly unusual for any prescriber or pharmacist to counsel a patient on this particular side effect.


4.     There may be side effects that are discovered years down the road.

One must also be aware that some side effects of a medication may not be apparent during clinical trials or even during the first few years that the medication is on the market. In some cases it may take 10, 15 or even 20 years to come to understand that rarest of side effects.  “Post marketing surveillance” is a term used to describe the monitoring that goes on after a medication is released on to the market. Post marketing surveillance has lead to some medications being removed from the market. One must always be aware that additional side effects of a medication may be revealed in the future through such post marketing surveillance.


5.     For any potential adverse effect, one must ask “how common” that side effect is.


For some medications, the chance of adverse effects may be very low, whereas for other medications, the chance of an adverse effect may be quite high. Let’s take topical minoxidil as an example. The most common side effects and headaches, dizziness, hair shedding (in the first few months), hair growth on the face and heart palpitations. However, in deciding whether to use the medication or not, patients need to understand the overall chance of these side effects.  For example, many women are extremely concerned to learn that hair growth on the face (hypertrichosis) is a potential side effect of minoxidil.  it is very important from women to note that 19 out of 20 women who use minoxidil will not have any problems with hair growth on face. However, 1 out of 20 users will. This information is helpful as it encourages many women to move forward with considering the medication with knowledge that their chance of hair growth on the face is quiet low.



Hair loss medications have the potential to dramatically improve hair density or stop hair loss and may improve quality of life. However, anyone using a treatment, no matter what the treatment actually is, needs to be aware that every treatment has potential side effects. It is imperative that patients, together with their doctors, spend time understand how common the various side effects actually are.



Dr. Jeff Donovan is a Canadian and US board certified dermatologist specializing exclusively in hair loss. To schedule a consultation, please call the Whistler office at 604.283.1887

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