Alopecia how long after the start of treatment?
When the fall begins, how it occurs, and why it can sometimes precede the first treatment.
Shedding timing refers to the timeline in which hair falls out after the start of chemotherapy. The loss generally begins two to three weeks after the first treatment, until the effect on the growing follicles becomes visible, then takes place over a few days to a few weeks depending on the protocol.
Hair loss does not occur from the first infusion. It most often begins two to three weeks after the first treatment, then can be progressive or rapid depending on the molecules and doses. With very alopecia protocols, it is often complete in a few days to a few weeks. In certain cases, a diffuse fall linked to the stress of the announcement can even precede the first treatment. Knowing this schedule allows you to anticipate it rather than endure it. This article details the stages of the fall, its variations and the guidelines for preparing for it.
After chemotherapy, hair usually begins to fall out two to three weeks after the first course. The fall can be progressive (by brushing handles) or rapid and massive depending on the protocol; with the most alopecic treatments, it is often complete in a few days to a few weeks. A diffuse fall related to the stress of the announcement can sometimes appear even before the start of treatment.
Pourquoi la chute ne survient pas from the first infusion
Many patients expect to lose their hair immediately after the first session. This is not how it happens. There is a delay, the time that the effect of the treatment on the growing follicles is visibly reflected on the surface of the scalp.
Cytotoxic agents act on the cells of the follicle matrix, which make the hair shaft. The weakening of this stem takes a few days to a few weeks to manifest itself in a fall. This is why the usual time frame is around two to three weeks after the first treatment.
- The fall does not start from the first infusion.
- It takes time for the effect on the follicle to become visible.
- The usual time frame is two to three weeks after the first treatment.
Le calendrier type de la chute
If each situation is unique, we can identify a typical chronology. The benchmarks below are indicative and vary depending on the molecules, the doses and the rhythm of the treatments.
| Moment | {00102}What’s happening: |
|---|---|
| Jour de la 1re cure | No visible changes |
| Weeks 2 to 3 | Usual start of hair loss: hair on the pillow, when brushing, when showering |
| Weeks 3 to 4 | Fall which intensifies; frequent scalp sensitivity |
| and above | Complete or partial fall depending on the protocol, until stabilization |
A feeling of tingling or sensitivity of the scalp sometimes accompanies the start of hair loss: this is common and not serious.
Progressive ou rapide : it depends on the protocol
The pace of the fall is not the same for everyone. Two main scenarios arise:
- Une chute progressive. Hair falls out in handfuls over several weeks, in a diffuse manner. This is common with moderate alopecia protocols.
- Une chute rapide et massive. With very alopecic protocols - combinations of taxanes and anthracyclines, for example — the fall can be almost complete in a few days to two weeks once initiated.
Faced with a rapid fall experienced as brutal, many patients choose to shave or cut it short at the first signs, to regain some control over the process.
- The fall can be gradual or rapid depending on the protocol.
- The most alopecia associations lead to a rapid fall.
- Cutting things short at the first signs helps some patients cope better with the transition.
Quand la chute precedes treatment
It may seem paradoxical to lose your hair even before the first treatment. However, it is possible, and the mechanism is not medicinal: it is the stress of the announcement of the diagnosis which is to blame.
An intense emotional shock can trigger telogen effluvium, a diffuse loss linked to the premature shift of hair towards the resting phase, in which cortisol is involved. This drop typically occurs a few weeks after the triggering event — it can therefore appear between the announcement and the start of treatment. It is generally reversible. We detail this mechanism in the article on traitements qui font perdre les cheveux.
Anticipate le moment de la chute
Knowing the calendar allows you to prepare concretely:
- Plan for the first few weeks. The fall most often happens around the second or third week: you can prepare for it rather than being surprised.
- Anticipate cutting. Shortening before the fall makes the transition less brutal and easier to manage on a daily basis.
- Prepare roofing solutions (scarves, prostheses) upstream, without precipitation.
- Prendre soin du cuir chevelu from this period, to preserve favorable soil for future regrowth.
Anticipating does not eliminate the fall, but transforms the way of living it: it means regaining a part of control over a process undergone.
Frequently asked questions
How long after the first session does the hair fall out?
Most often two to three weeks after the first treatment. The fall can then be gradual or rapid depending on the protocol.
La chute est-elle brutale ou progressive ?
It depends on the treatment. Moderately alopecic protocols lead to a gradual fall by handfuls; the most alopecic, a rapid and almost complete fall in a few days to two weeks.
Can you lose your hair before the first treatment?
Yes, in certain cases: the stress of the announcement can trigger a diffuse fall (telogen effluvium) even before the start of treatment. It is generally reversible.
Pourquoi mon cuir chevelu est-il sensible quand les cheveux tombent ?
A tingling sensation or tenderness frequently accompanies the onset of hair loss. It's common and not serious.
Should you shave your hair as soon as it begins to fall out?
This is not an obligation, but many patients choose to cut short or shave at the first signs to better experience the transition. It's a personal choice.
This guide is published by the Laboratoire RENASCOR Paris, a French cosmeceutical laboratory specializing in hair reactivation and reconstruction since 2017, and its founder Stéphane Paulet. Our approach is based on a principle: we rebuild before stimulating. Discover our scientific approach and our sources.
Pour aller plus loin
This page is intended for information. It does not replace any medical advice and does not constitute an individual promise of results. The time benchmarks are indicative and vary depending on the person and the protocols.