Hair Loss Causes

Minoxidil Shedding

Young woman holding handful of minoxidil shedding hair.

Minoxidil is a commonly used treatment for male and female pattern hair loss. It’s been found to be beneficial for hair growth in all areas of the scalp, but is especially good at helping restore hair density at the vertex, or crown of the head. But did you know that like finasteride, it can also induce temporary shedding in some patients? Fortunately, this is temporary and short-lived. Read on to find out more about minoxidil shedding, why it happens, when it’s most likely to happen and how long it lasts.

What is minoxidil shedding?

Minoxidil shedding, or minoxidil-induced telogen effluvium, refers to a temporary increase in hair loss associated with starting minoxidil treatment (in oral or topical form). It is self-limiting and typically goes away once hair follicles adjust to a new hair growth cycle.

Why does minoxidil cause shedding?

Ironically, hair loss treatments like minoxidil can induce a temporary increase in shedding shortly after beginning treatment. Why does this happen? Let’s start with a quick refresher on the hair growth cycle.
There are four different stages of the hair growth cycle:

  • Anagen phase: During this growth phase, hair follicles start to push hairs out from the root. This growth phase can last several years. At any time, most hairs (between 70-90%) on the scalp are in the anagen phase.

  • Catagen phase: Catagen is a brief transition phase when your hair stops actively growing. This phase usually lasts 2-3 weeks and during this time, the hair follicle itself begins to shrink. The root end of the hair smooths over and it’s held in place until the shedding phase.

  • Telogen phase: Telogen is also referred to as the rest phase of the growth cycle. Approximately 10-30% of hairs on the scalp can be found in this phase, which typically lasts a few months. New cells start to gather at the bottom of the hair follicle, pushing the old hair out. This is also when the hair follicle returns to its original shape.

  • Exogen phase: Exogen simply refers to the process of shedding telogen hairs. It’s normal to lose about 100 hairs a day.

  • Minoxidil acts to help extend the anagen (growth) phase of the hair growth cycle (Badri et al., 2023). As hair follicles adjust to new growth cycles, older hairs are shed. This change is usually the most dramatic right after starting minoxidil, as old hairs are pushed out of hair follicles to make room for new growth.

    Is minoxidil shedding a good sign?

    Yes, in most cases shedding associated with starting minoxidil treatment simply indicates that hair follicles are responding to the medication. In most cases shedding will stop on its own.

    When does minoxidil shedding start? When does minoxidil shedding stop?

    It’s important to be aware that not all patients will experience shedding while taking minoxidil. When it does occur, experts generally agree that it begins within the first three months of taking the medication. Like finasteride shedding, it’s not usually a cause for concern and should resolve itself within a few months.

    How long does minoxidil shedding last?

    Generally, minoxidil shedding lasts 4-8 weeks. If shedding continues for more than four months, we recommend bringing this to your doctor’s attention, as it could be a sign of an underlying medical condition that is causing your hair loss. Don’t fret– chances are, if your hair just isn’t responding to minoxidil, there are other treatment options. Your doctor can walk you through some alternatives.

    Minoxidil shedding: Takeaway

    For some patients, starting a hair loss treatment like minoxidil can result in increased shedding. In most cases, this is a sign that hair follicles are responding to minoxidil’s effects on the hair growth cycle. With continued use of minoxidil, shedding should stop and you’ll begin to notice improvements in hair density and thickness. If you’re worried about minoxidil shedding, we encourage you to speak with your doctor, who can help determine whether your response is normal or requires additional investigations.

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