Telogen effluvium vs androgenetic alopecia: how to differentiate them?

Telogen effluvium vs androgenetic alopecia: how to differentiate them?

Understanding two major biological mechanisms of hair loss to better support regrowth.

Hair loss never has a single origin. It can be reactive, abrupt, and diffuse — this is telogen effluvium — or on the contrary hormone-dependent, progressive, and localized — this is androgenetic alopecia.
For a patient, the two may appear similar.
For an expert, they are two opposite biological stories, requiring tailored responses.

Accurately differentiating these mechanisms allows to:

• avoid misinterpretations,

• choose the right treatments,

• and understand why density evolves differently depending on the context.

1. What is telogen effluvium?

The reactive, abrupt, and diffuse hair loss

1.1 Definition

Telogen effluvium occurs when a large number of hair follicles prematurely enter the telogen phase, the resting phase of the hair cycle.
A few weeks later, they all fall out at the same time, creating a massive and impressive hair loss.

1.2 The most common causes

🔹 Biological causes

• Chemotherapy, heavy treatments

• Acute illness, prolonged fever

• Childbirth

• Surgical intervention

• Sudden weight loss

• Deficiencies (iron, zinc, proteins)

🔹 Psycho-emotional causes

• Chronic stress

• Burnout

• Emotional shock (bereavement, separation)

• Hypercortisolism

🔹 Environmental causes

• Seasonality

• Thyroid dysfunction

• Occasional hormonal changes

1.3 How to recognize telogen effluvium?

• Sudden hair loss ("clumps of hair")

• Diffuse loss, without bald spots

• Hair falling out whole, without miniaturization

• Strands maintaining their diameter

• Appearance of many "baby hairs" if the cause is resolved

• Scalp sometimes more sensitive

1.4 Duration and evolution

Telogen effluvium is reversible.
Regrowth generally starts after 6 to 12 weeks, and density is restored in 3 to 6 months — sometimes longer in the case of chronic effluvium.

2. What is androgenetic alopecia?

The progressive, hormone-dependent, and localized hair loss

2.1 Definition

Androgenetic alopecia (in men and women) corresponds to an abnormal sensitivity of the follicle to DHT (dihydrotestosterone).
This is not an excess of hormones:
It is the follicle that reacts too strongly to them.

As a result:

• progressive shortening of anagen cycles,

• miniaturization,

• increasingly fine strands,

• diminishing density over the years.

2.2 Affected areas

In men

• Temporal recesses

• Vertex

• Crown

• Progression in "M", then in "U"

In women

• Widening of the central part

• Weakened density on top

• Forehead better preserved

2.3 Typical signs

• Progressive, slow loss

• Strands that miniaturize

• Hair shorter, finer

• Specific areas affected

• Frequent family history

2.4 Duration and evolution

Without appropriate management, androgenetic alopecia is progressive and lasting.
Follicles miniaturize until exhaustion.

3. Telogen effluvium vs androgenetic alopecia: the comparative table

4. The RENASCOR approach: understand to better rebuild

✔ In telogen effluvium

Objective: reduce inflammation, restart the anagen phase, restore hair synchronization.

• REDACTIV1 treatments (post-chemotherapy)

• REDACTIV2 treatments

• Suitable shampoos (soothing, densifying)

✔ In androgenetic alopecia

Objective: slow down miniaturization, optimize vascularization, support regrowth.

• REDACTIV2

• Densifying or regulating shampoo depending on scalp quality

Each RENASCOR protocol is based on proven biological mechanisms and a fine understanding of hair cycles.

5. FAQ — Most searched questions

1. How can I know if I have androgenetic alopecia or telogen effluvium?

Look at the speed of evolution:

• If the loss is massive and rapid, it is telogen effluvium;

• If the density is thinning slowly, it is androgenetic alopecia.

2. Can telogen effluvium make me bald?

No.
It does not destroy follicles: it puts them in temporary rest.

3. Can telogen effluvium last a year?

Yes, if it becomes chronic (cause unresolved).

4. Why is my part widening?

This is typical of female androgenetic alopecia.

5. Does androgenetic alopecia necessarily start early?

No.
It can start at 18 or 55 years old, depending on individual sensitivity.

6. Can you have both at the same time?

Yes: androgenetic alopecia can be decompensated by telogen effluvium.