How can I tell if my hair loss is temporary or permanent?

The duration of the hair loss

Temporary hair loss, also known as acute telogen effluvium, usually occurs 2 to 3 months after a triggering event: intense stress, illness, nutritional deficiency or hormonal changes. It lasts on average 3 to 6 months, then gradually stabilises. Conversely, chronic hair loss is a long-term condition. It can develop over several years, with hair density decreasing slowly but steadily.

CONCLUSION: if hair loss persists for more than 6 months without any visible improvement, a thorough investigation into the causes should be considered (androgenetic alopecia, autoimmune disorder, chronic condition) (5).

The amount of hair lost

It is normal to lose between 50 and 100 hairs a day. In the case of temporary hair loss, this amount may double or even triple, but remains spread evenly across the entire scalp. With permanent hair loss, the loss may seem less dramatic on a day-to-day basis, but the hair gradually thins, particularly in specific areas (temples, centre parting, and the top of the head, known as the vertex). Trichoscopy (microscopic examination of hair) reveals progressive miniaturisation of the follicles in chronic cases (3).

CONCLUSION: Massive but uniform hair loss suggests a temporary episode; gradual, localised thinning suggests permanent hair loss.

The appearance of the scalp and hair

In cases of temporary hair loss, the hairs that fall out are often long, with a visible white root: they have simply reached the telogen phase (the resting phase of the hair cycle). In cases of permanent hair loss, there is a reduction in hair diameter, finer regrowth, and sometimes thinning patches visible in the light. Recent studies show that chronic stress can induce sympathetic hyperactivation, which directly affects the hair follicle (1).

CONCLUSION: if the quality of your hair changes permanently (becoming finer and more brittle), the hair loss could be structural.

The triggering factor

Temporary hair loss almost always occurs in response to an identifiable trigger: childbirth, infection, a restrictive diet or acute stress. It tends to appear some time after the trigger. Permanent hair loss can be genetic, hormonal or autoimmune in nature. It sometimes develops without any obvious trigger. More than 50 per cent of men and around 40 per cent of women will experience androgenetic alopecia (hormone-related hair loss) at some point in their lives (2).

CONCLUSION: if there is no specific factor to explain the hair loss, a long-term cause should be investigated.

In reality, there are significant differences between the two sexes:

• In men, permanent hair loss is predominantly androgenetic in origin. It follows a typical pattern: receding temples followed by thinning at the crown. This is commonly referred to as baldness.

• In women, hair loss is more often diffuse. Female androgenetic alopecia manifests itself primarily as a gradual widening of the central parting. Hormonal factors (postpartum, pre-menopause) play a decisive role.

Transient forms, on the other hand, affect men and women in a similar way, but are more frequently reported in women following a hormonal event.

If hair loss persists for more than half a year, becomes more severe or is accompanied by other symptoms (unusual tiredness, hormonal imbalances, changes to the menstrual cycle, an itchy scalp), a medical check-up may be advisable. The aim? To identify any underlying factors that may be contributing to the hair loss.

A healthcare professional may recommend several tests, tailored to your specific situation:

• A blood test including ferritin, zinc, vitamin D, vitamin B12, etc.

• A thyroid hormone test to assess thyroid function

• A hormonal assessment if androgenetic alopecia or ovarian imbalance is suspected

• A trichoscopy (dermoscopy of the scalp) to assess follicular density and look for any signs of miniaturisation.

These types of tests help to objectively identify iron deficiency – which is common in women – a thyroid disorder or an early stage of hormonal alopecia. It also serves as a reminder that hair loss is often multifactorial: genetic predisposition, chronic stress, silent inflammation and nutritional deficiencies can all coexist. Combining a medical approach with nutritional support and appropriate topical treatments therefore offers a coherent and personalised strategy, without pitting conventional medicine against natural therapies.

A word from the trichologist

"The first signs of permanent hair loss, which are not always noticeable, may include: a gradual widening of the central parting, sometimes only visible when comparing photos taken several months apart; a receding hairline with a visually longer forehead; thinning at the temples; a loss of density in the ponytail, with a reduced diameter; a reduction in volume making it difficult to tie all the hair back with a hairband, hair that feels finer to the touch than before (gradual miniaturisation), the appearance of short, fine hairs on the forehead… But also hair that appears flatter, with increasing difficulty in adding volume or styling it, slower regrowth than before, and a chronic but moderate increase in daily hair loss, without any episodes of massive shedding. And finally, the more frequent presence of hair on the floor, on surfaces around the home, on the pillow, on the hairbrush or whilst shampooing. These signs are often gradual and subtle at first, which explains why they may go unnoticed for several months."

Dalila Belmokhtar, @dalilahairscience, Doctor of Pharmacy & trichologist

A word from the naturopath

"Before discussing treatments, it is very helpful to understand the individual’s overall condition and the key issues to address: chronic stress, iron or zinc deficiencies, thyroid or androgenic imbalances, low-grade inflammation… All these factors directly influence the hair growth cycle and interact with one another. The hair follicle is, moreover, a living tissue, particularly sensitive to hormonal, nutritional and neurological fluctuations. Thus, hair loss is never an isolated issue: it reflects the body’s adaptation to a wider imbalance. Working on lifestyle, stress management, as well as diet and sleep quality, therefore allows for a profound and lasting intervention, complementing local treatments.”

Lou Dumas, naturopath

In the event of severe, sudden hair loss, or hair loss accompanied by patches, significant itching or unusual tiredness, medical advice is essential. Blood tests and further investigations may be necessary.

When faced with hair loss, attention often focuses on the amount of hair found on the brush or in the shower. However, this single factor does not always reflect the reality of the situation. Changes in overall density, the width of the centre parting or even the texture of the hair provide equally valuable insights into what is actually happening. Taking a step back and observing the hair as a whole, rather than focusing on a single moment, helps to avoid jumping to conclusions. Some people, for example, choose to photograph their scalp at regular intervals, under the same lighting conditions: this objective approach helps to distinguish a temporary impression from a structural change. Visual analysis over time often proves more reliable than the emotional perception of the moment, which can be amplified by anxiety or tiredness.

Lou graduated from HEC in 2012. She gained ten years of experience in marketing for cosmetics and perfumes before becoming an independent consultant in this field. She recently completed a three-year naturopathy program at the European College of Holistic Naturopathy (CENATHO, Paris) with the goal of supporting the physical and mental health of the people she works with through a holistic approach to lifestyle.