Haidak Medical Journalist Director Yongwook YongㅣSource: Haidak
Minoxidil is a popular product for people with thinning hair. People who start using minoxidil to restore hair will experience symptoms where more hair starts to fall out over a short period of time. This symptom is called ‘shadowing’.
There are many clinical trials and medical evidence supporting the effectiveness of minoxidil for moderate hair loss due to alopecia. But how do we know if it really works, especially if there is a side effect of more hair falling out after using minoxidil? Let’s take a closer look at minoxidil-induced shedding to help you understand how common it is, what causes it, and whether it’s something to worry about.
How does minoxidil work?
Minoxidil is a drug originally developed to treat high blood pressure. Researchers have observed hair regrowth in hypertensive patients with alopecia after taking minoxidil, which led to the creation of the world’s most popular over-the-counter hair loss treatment. People have been using minoxidil to treat hair loss since 1986.
Minoxidil’s mode of action is not entirely clear. What is clear is that minoxidil increases hair growth while reducing hair loss in some people. However, it doesn’t work for everyone.
Minoxidil is also classified as a vasodilator because, when applied, it works by dilating the blood vessels to allow blood to flow more easily to the affected area. Increased blood circulation to the scalp may be one of the reasons why minoxidil promotes hair growth.
Minoxidil and the hair growth cycle
Hair follicles go through four stages of growth. Not all hair follicles are in the same stage at once. Minoxidil is known to affect two stages of hair growth.
Stage of hair follicle growth｜Source: New Hair Hair Plastic Surgery Clinic
Anagen Phase: The ‘growth’ phase is the telogen phase of hair growth. This is when the hair is pushed out from the root. Using minoxidil can extend the length of the telogen phase.
Telogen Phase: The telogen phase is the ‘resting phase’ of the hair, where growth is complete but not yet ready to fall out. In clinical trials, minoxidil shortens the telogen phase of hair from 20 days to 1-2 days.
What causes minoxidil loss?
The side effects of minoxidil are usually mild. Common side effects include mild itching and burning, and peeling of the skin. Minoxidil can cause hair loss, especially when first used. Also, because minoxidil accelerates the hair shedding phase, it can sometimes cause hair to fall out faster than usual.
However, minoxidil also prolongs the hair growth period. This means that even if you expect some hair loss at first, new hair will soon grow to replace the lost hair. Although not everyone experiences shedding as a side effect of minoxidil, some people can experience severe shedding. There are currently no statistics examining the prevalence of this particular side effect.
Can minoxidil prevent hair loss?
There is little you can do to prevent hair loss associated with minoxidil, and you cannot predict whether hair loss will occur when you first start using the product. One caveat is that the higher the concentration of minoxidil, the stronger the side effects can be. For example, using a product with a 2% concentration of minoxidil may cause fewer side effects than using a product with a 5% concentration.
How long does minoxidil hair loss last?
The effects of minoxidil vary from person to person. It usually takes about 8 weeks for consistent use of minoxidil to start seeing the benefits. And after about 4 months, the shading phenomenon should stop and the hair should start growing.
If you are still losing hair after 4 months, it may not be related to minoxidil. If you are losing a lot of hair even after 4 months of use, it is advisable to discuss other treatments with your doctor.
In summary, it is normal to see an increase in hair loss due to slight hair loss after you start using a topical product that contains minoxidil. You may be worried, but in general, you don’t have to worry because hair loss caused by shading will grow back.
However, if hair loss does not stop within 4 months of starting hair therapy with minoxidil, you should stop using it and discuss other hair loss treatment options with your doctor.
Written = Director Yong-wook Ko, medical journalist in Haidak (family medicine specialist)
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