A temporary shedding phase is a well-documented and normal side effect some people might notice in the first few weeks of hair loss treatment with finasteride and/or minoxidil. But what about a random shedding phase when you’ve been using hair loss treatment for months, or even years?
While there’s good evidence that starting treatment can lead to an initial shedding phase, often referred to as the ‘dread shed’, there’s little evidence for shedding episodes during long-term treatment.
In this blog, we’ll cover what shedding phases could mean, is it something to worry about, and can you do anything to stop it?
What is hair shedding?
It’s normal to shed between 50 and 100 hairs every day, because the shedding phase is a normal and necessary part of the hair growth cycle. The hair growth cycle looks like this:
- Anagen – the active growth phase
- Catagen – the transition phase between anagen and the next phase. The hair detaches from the base of the follicle and stops growing.
- Telogen – the shedding phase. The old hair has stopped growing and is waiting to be shed.
- Exogen – the transition back to anagen. A new hair starts to grow from the base, pushing the old hair out.
A shedding phase is characterized by losing more than 100 hairs a day. It means there is an imbalance in the ratio of anagen hairs to telogen hairs – more hairs are in the telogen phase than usual, leading to increased shedding.
Now, we’ll cover the possible explanations for shedding episodes.
Synchronized hair follicles
You might notice a shedding phase later down the line during treatment because a proportion of your hair follicles are on the same schedule in their hair growth cycle.
Before treatment, DHT gradually disrupts the normal hair growth cycle. Hair follicles spend less time growing and more time resting, while the hairs themselves become thinner and shorter.
Once you start treatment, the aim is to reverse these effects.
Finasteride lowers DHT levels, helping to protect follicles from further miniaturisation. Minoxidil is thought to shorten the resting phase and prolong the growth phase, while also improving blood flow around the follicle to support healthy hair growth.
As these miniaturised follicles begin returning to a healthier growth cycle, they first need to shed the old resting hair to make way for a new growing one. That's why some people notice increased shedding shortly after starting treatment.
But hair follicles follow fairly predictable growth cycles. If a group of follicles enters a resting phase around the same time, it's possible to notice periods of increased shedding later on, even while treatment is working as intended.
In other words, a temporary increase in shedding doesn't automatically mean you're losing ground.
Missing doses/inconsistency
Another common cause of shedding is inconsistency.
Hair loss treatments work best when they're taken regularly. Missing doses from time to time isn't likely to have a major impact, but repeatedly stopping and starting treatment can.
With finasteride, inconsistent use can allow DHT levels to rise again, reducing the treatment's protective effect on the follicles.
Minoxidil works by supporting the hair growth cycle and maintaining an environment that encourages growth. If you're using it irregularly, those benefits may become less consistent.
An erratic routine can disrupt the hair cycle and, in some cases, contribute to increased shedding.
If you've recently noticed more hair fall, it's worth asking yourself whether anything has changed in your treatment routine before assuming the medication has stopped working.
Switching treatment
Switching treatment can also trigger a new round of shedding. This could involve switching from one formulation to another (e.g switching from topical minoxidil to oral minoxidil), switching to a new active ingredient or adjusting dosage.
Researchers investigated whether continuing treatment with topical Minoxidil during the transition to using oral minoxidil could reduce the risk of shedding.
In one 70089-9/abstract" target="_blank" rel="noopener noreferrer">study of 115 patients starting oral minoxidil, 37 overlapped treatments during the transition. Only six participants experienced a shedding phase, and the researchers found no significant difference between those who overlapped treatments and those who didn't.
In other words, continuing topical minoxidil didn't appear to reduce the risk of shedding during the switch.
That said, the study had several limitations. It relied on a small sample size, self-reports by the patients rather than objective data, and it was a retrospective study on past records rather than a controlled clinical trial.
Based on this evidence, we know that changes to treatment can trigger an episode of increased shedding, but overlapping treatments for a short period doesn’t appear to reduce the risk.
Is it possible for hair loss treatment to become less effective over time?
Some people worry they will build up a tolerance to the medications, or it will get less effective over time.
Scientists use the term ‘tachyphylaxis’ to describe a medication becoming less effective because the body has adapted to it. There is little evidence that this happens with either finasteride or minoxidil.
One of the longest finasteride studies ever conducted followed 523 men using finasteride 1mg for 10 years. After a decade of treatment, 91.5% saw an improvement, and hair loss improved or did not progress in 99.1%. In other words, their hair loss either got better or did not get any worse. Researchers found no evidence that finasteride's effectiveness wore off over time. If anything, the results suggest that finasteride can remain effective for many years when taken consistently.
A similar pattern was seen with Minoxidil Spray treatment in this study. Men treated with topical minoxidil 5% saw results peak one year into treatment, with hair count for all participants remaining above baseline (before treatment began). This means Minoxidil tends to deliver most of its regrowth benefits in the first year of treatment, and then effectively maintains them with continued treatment.
Have you considered if your hair loss could be driven by another factor?
The shedding might not be related to your treatment at all.
Finasteride and minoxidil are designed primarily to treat male pattern baldness. They aren't able to prevent every form of hair loss.
One of the most common alternative causes is telogen effluvium.
Telogen effluvium occurs when a significant physical or emotional stress pushes a large number of hairs into the resting phase at the same time. Common triggers include surgery, illness, childbirth, severe stress, or rapid weight loss.
Unlike male pattern baldness, telogen effluvium tends to cause sudden, diffuse shedding across the entire scalp. It often appears two to three months after the triggering event and is usually temporary.
There are other causes of hair loss, too. Traction alopecia, for example, occurs when repeated tension on the hair follicles causes damage over time. It’s often caused by wearing tight hairstyles or headwear regularly,
If you're experiencing sudden or significant shedding despite sticking to your treatment plan, it's worth considering whether another form of hair loss could be involved.
All of our blog articles are reviewed by our Medical Director before publication.
